Past day verification and analysis:
Updates:
Synoptic Analysis: Cold air damming will continue today and tomorrow causing unseasonably cool weather. Dry and seasonable weather will occur on Wednesday and Thursday. A chance of afternoon thunderstorms along with seasonably warm conditions through the weeked.
Near term (12 hr): Short AFD today as more attention will be paid to verification later. Chance of light showers and drizzle will continue through the Tuesday due to cold air damming high which will settle over the great lakes region. Will go unseasonably cool this afternoon and two categories below climatology tomorrow. Front will stalled to the east keeping clouds through tomorrow.
Short term ( 12 -60 hr): Cold air damming will begin to erode by mid week but potentially reignite later on Thursday into the night. Will go seasonably cool and mostly cloudy with decreasing clouds in the afternoon on Wednesday. Dry air will hinder precip on Thursday. Potential overrunning even Thursday night as a weak low pressure forms off the coast. Will pay more attention to this tomorrow.
Long term (Beyond 60 hr): Raleigh will stay down stream of the trough axis just west of the mountains. Southerly winds will bring more seasonable temps and increase chances for afternoon convection through the weekend. Will go summer climatological on pops with climatological to a category above for high. Not too worried about timing in the long term.
Forecast:
Monday afternoon: drizzly with scattered showers high 69
Monday night: drizzly with scattered showers low 67
Tuesday: Cloudy with a chance of drizzle High 75 Low 67
Wednesday: Mostly cloudy with decreasing clouds in the afternoon High 81 Low 60
Thursday: Partly cloudy in the morning with increasing clouds in the afternoon High 79 low 64 30% chance showers overnight.
Friday: Cloudy in the morning with decreasing clouds in the afternoon. 30% chance storms High 80 Low 66
Saturday: Partly cloudy with a 30% chance afternoon storms high 84 low 67
Sunday: Partly cloudy with a 30% chance of afternoon storms high 86 low 69
Review of RAH AFD:
Monday, August 31, 2009
Sunday, August 30, 2009
Past day verification and analysis:
Updates:
9:16 PM: Upped chances tonight due to precip associated with the northern book end line echo moving up from the south. May lower precip amounts tomorrow based on 0z models. 6z GFS weakens 850 low and centers it south of the area... will wait and see if that trend continues... still expecting a heavy band of precip to set up near the 850 low but may weaken as it moves through the triangle. Expect this band to move through tomorrow morning through lunch.
10:45 PM: 0z NAM has weaker 850 low (compared to GFS) passing very close to the triangle... The NAM actually squeezes out a good 1.25 inches qpf but in a relatively small area. Error margin is pretty and confidence of exact location of heaviest rain is not high. Rain total could be anywhere from .25 to 1.5 inches qpf based on strength and location of 850 low. I'm not staying up for the GFS so will just leave wording as is... but will mention rain mostly occuring in the morning.
Synoptic Analysis:
Cloudy and seasonably cool conditions will persist through the afternoon and early evening. A steady rain and unseasonably cool weather is likely on Monday with chances of scattered showers lasting through the middle of the week. Dry and seasonable conditions will occur at the end of the week.
Near term (12 hr): Will lessen chance of storms for today. Surface front has just passed the region. GSO sounding reveals backing and a mid level capping inversion. Expect CAPE values to remain low despite a good chance for some breaks in the cloud by mid afternoon. NAM sim radar keep precip to our south east where cloud cover is much left prevalent... and where the front has yet to pass. Mechanism for ascent will remain toward our southwest today and this evening. Some elevated convection does exist behind the front and more of this could pop up this afternoon. Temps will be slow to cool as is usually the case. Will go with below climatological chance pops for the afternoon for risk of elevated storms with chance pops late night as the synoptic plays a bigger role.
Short term ( 12 -60 hr):
A low pressure will begin to strengthen slightly and move northeast across North Carolina. Warm air out ahead of this low pressure will surge over cold air provided by a surface high over the great lakes. Expect cold air to dam into the region at the surface. Isentropic upglide will be a primary mechanism for ascent in what looks to be a fairly wide spread precip event to the N and NE of the low level vorticity. The speed and location of the low will determine how much precip falls in Cary. NAM doesn't really seem to be picking up on any damming so will lean toward the GFS which shows us to be in the right entrance region of an upper level jet. The GFS also has the 850mb low traveling directly over the region thus enhancing the precip. This setup looks to dump some significant precip. Tough call on the exact location but will put it all out there and call for an inch. MUCAPE will be limited but isolated thunder is possible. Despite decent shear and helicity severe weather is unlikely due to low CAPE. Conditions will remain cold air damming like after the rain moves through. Drizzly... cool.. cloudy
Long term (Beyond 60 hr):
The high in the NE will begin to weaken and open up and most of the cloudiness will exit the area... however.. the pattern will remain seasonably cool.. but dry
Forecast:
Sunday afternoon: 20% chance of storms this afternoon. precip < .1 inch High 83
Sunday night: 80% chance of showers and storms. Low 70
Monday: 90% chance of rain mainly in the morning. 50% chance overnight. About an inch of precip High 68 Low 65
Tuesday: Mostly cloudy with scattered showers (40%). precip <.1 High 77 Low 62
Wednesday: Mostly sunny high 81 low 61
Thursday (Gameday!): Mostly sunny high 80 Low 61
Friday: Partly cloudy high 80 low 63
Saturday: Partly cloudy high 85 low 68
Review of RAH AFD: RAH believe 850 low is too strong as represented by the GFS... therefore... they went with less qpf. It will be interesting to find out who is right on this one. I mentioned front earlier but I should've mentioned it stalling on the coast.
Updates:
9:16 PM: Upped chances tonight due to precip associated with the northern book end line echo moving up from the south. May lower precip amounts tomorrow based on 0z models. 6z GFS weakens 850 low and centers it south of the area... will wait and see if that trend continues... still expecting a heavy band of precip to set up near the 850 low but may weaken as it moves through the triangle. Expect this band to move through tomorrow morning through lunch.
10:45 PM: 0z NAM has weaker 850 low (compared to GFS) passing very close to the triangle... The NAM actually squeezes out a good 1.25 inches qpf but in a relatively small area. Error margin is pretty and confidence of exact location of heaviest rain is not high. Rain total could be anywhere from .25 to 1.5 inches qpf based on strength and location of 850 low. I'm not staying up for the GFS so will just leave wording as is... but will mention rain mostly occuring in the morning.
Synoptic Analysis:
Cloudy and seasonably cool conditions will persist through the afternoon and early evening. A steady rain and unseasonably cool weather is likely on Monday with chances of scattered showers lasting through the middle of the week. Dry and seasonable conditions will occur at the end of the week.
Near term (12 hr): Will lessen chance of storms for today. Surface front has just passed the region. GSO sounding reveals backing and a mid level capping inversion. Expect CAPE values to remain low despite a good chance for some breaks in the cloud by mid afternoon. NAM sim radar keep precip to our south east where cloud cover is much left prevalent... and where the front has yet to pass. Mechanism for ascent will remain toward our southwest today and this evening. Some elevated convection does exist behind the front and more of this could pop up this afternoon. Temps will be slow to cool as is usually the case. Will go with below climatological chance pops for the afternoon for risk of elevated storms with chance pops late night as the synoptic plays a bigger role.
Short term ( 12 -60 hr):
A low pressure will begin to strengthen slightly and move northeast across North Carolina. Warm air out ahead of this low pressure will surge over cold air provided by a surface high over the great lakes. Expect cold air to dam into the region at the surface. Isentropic upglide will be a primary mechanism for ascent in what looks to be a fairly wide spread precip event to the N and NE of the low level vorticity. The speed and location of the low will determine how much precip falls in Cary. NAM doesn't really seem to be picking up on any damming so will lean toward the GFS which shows us to be in the right entrance region of an upper level jet. The GFS also has the 850mb low traveling directly over the region thus enhancing the precip. This setup looks to dump some significant precip. Tough call on the exact location but will put it all out there and call for an inch. MUCAPE will be limited but isolated thunder is possible. Despite decent shear and helicity severe weather is unlikely due to low CAPE. Conditions will remain cold air damming like after the rain moves through. Drizzly... cool.. cloudy
Long term (Beyond 60 hr):
The high in the NE will begin to weaken and open up and most of the cloudiness will exit the area... however.. the pattern will remain seasonably cool.. but dry
Forecast:
Sunday afternoon: 20% chance of storms this afternoon. precip < .1 inch High 83
Sunday night: 80% chance of showers and storms. Low 70
Monday: 90% chance of rain mainly in the morning. 50% chance overnight. About an inch of precip High 68 Low 65
Tuesday: Mostly cloudy with scattered showers (40%). precip <.1 High 77 Low 62
Wednesday: Mostly sunny high 81 low 61
Thursday (Gameday!): Mostly sunny high 80 Low 61
Friday: Partly cloudy high 80 low 63
Saturday: Partly cloudy high 85 low 68
Review of RAH AFD: RAH believe 850 low is too strong as represented by the GFS... therefore... they went with less qpf. It will be interesting to find out who is right on this one. I mentioned front earlier but I should've mentioned it stalling on the coast.
Friday, August 28, 2009
Fri Aug 28
Past day verification and analysis: No precip high 94 low 72. Precip coverage was less than 30% likely due to dry air aloft along with capping inversion around 650mb. Will take that into account in future forecasts.
Synoptic analysis: A closed low in the deep south will open up and converge with Tropical Storm Danny. Thunderstorm chances will increase this afternoon. A chance of storms will continue on Saturday. A cold front will begin to push into the region on Sunday and stall early next week providing a good chance of showers and thunderstorms. Cooler and drier conditions will invade the region by next week.
Near term (12 hr): A very interesting but fairly difficult forecast. The closed off upper level low will become an open wave and converge with Tropical Storm Danny. The juxtaposition of these two features will create a dynamic and complicated scenario this afternoon. A zone of surface convergence should set up near the piedmont later this afternoon. Upper level support isn't too impressive... still anticipate likely chance for convective development this afternoon. Precip on the wet side of Danny's circulation is hardly in existence with westerly shear having sheared most of the precip to the east of the center... therefore am less concerned with direct precip from Danny. Breaks in the cloud cover should enhance SBCAPE above 2000 J/Kg by this afternoon. PW values of 1.8 to 1.9 inches are currently in the region. There is also no sign of a capping inversion therefore expect storms with heavy rain to develop along regions of convergence. Will go likely PoPs this afternoon and high chance overnight. High around climatology due to cloud cover and low slightly higher than persistence due to the same reasoning.
Short term ( 12 -60 hr): Attention will shift from tropical storm Danny and the upper level low in the south toward the strengthening and transient upper low near the great lakes. A relatively strong cold front will approach the area from west increasing rain chances through Sunday afternoon. We have a good chance for storms Saturday afternoon being in the warm sector. A 500 mb impulse will move through Saturday night therefore will keep high chance PoPs through the night on Saturday. Will go with climatological high and persistent low. Cloud cover and showers will impact lows. Will lower PoPs on Sunday to high chance. Increased shear will improve storm organization, but most of the upper level dynamics will be to the west. Severe threat will increase but not enough to warrant anything other than a mention at this time.
Long term (Beyond 60 hr):
Trough will deepen and the cold front will stall and weaken in the early part of the week bringing a chance for showers and storms on Monday and Tuesday before slowly moving past the region. Will go high chance on Monday and Tuesday. Once confidence grows in the timing of the front and upper level support. Autumn weather will invade the area after the passage of the front through the end of the week.
Forecast:
Friday afternoon: 60% chance of storms with heavy rain possible at times. Precip .25 inches but higher in storms. High 86
Friday night: 40 % chance of showers and storms.. precip less than .1 inches
Saturday: 40 % chance of showers and storms through the night.. precip less than .1 inches High 89 low 72
Sunday: 50 % chance of showers and storms mainly before 10 pm.. precip .1 - .25 inches High 89 low 72
Monday: 40% chance of showers and storms after 2 pm High 85 low 72
Tuesday: 40% chance of showers and storms through the night. High 85 Low 72
Wednesday: Mostly cloudy in the morning partly cloudy in the afternoon High 81 Low 65
Thursday: Partly Cloudy High 79 Low 60
Review of RAH AFD: Need to watch for dry air on Saturday. Keep a good eye out on upper divergence as well. A lot of stuff to look at through with a full forecast. RAH breaks it up into several sections. Precip early next week may be some overrunning. When looking at theta e to determine position of front need to consider that part of the hold up is due to downsloping effect. So I need to look at the pressure field and wind direction to determine if front has passed.
Synoptic analysis: A closed low in the deep south will open up and converge with Tropical Storm Danny. Thunderstorm chances will increase this afternoon. A chance of storms will continue on Saturday. A cold front will begin to push into the region on Sunday and stall early next week providing a good chance of showers and thunderstorms. Cooler and drier conditions will invade the region by next week.
Near term (12 hr): A very interesting but fairly difficult forecast. The closed off upper level low will become an open wave and converge with Tropical Storm Danny. The juxtaposition of these two features will create a dynamic and complicated scenario this afternoon. A zone of surface convergence should set up near the piedmont later this afternoon. Upper level support isn't too impressive... still anticipate likely chance for convective development this afternoon. Precip on the wet side of Danny's circulation is hardly in existence with westerly shear having sheared most of the precip to the east of the center... therefore am less concerned with direct precip from Danny. Breaks in the cloud cover should enhance SBCAPE above 2000 J/Kg by this afternoon. PW values of 1.8 to 1.9 inches are currently in the region. There is also no sign of a capping inversion therefore expect storms with heavy rain to develop along regions of convergence. Will go likely PoPs this afternoon and high chance overnight. High around climatology due to cloud cover and low slightly higher than persistence due to the same reasoning.
Short term ( 12 -60 hr): Attention will shift from tropical storm Danny and the upper level low in the south toward the strengthening and transient upper low near the great lakes. A relatively strong cold front will approach the area from west increasing rain chances through Sunday afternoon. We have a good chance for storms Saturday afternoon being in the warm sector. A 500 mb impulse will move through Saturday night therefore will keep high chance PoPs through the night on Saturday. Will go with climatological high and persistent low. Cloud cover and showers will impact lows. Will lower PoPs on Sunday to high chance. Increased shear will improve storm organization, but most of the upper level dynamics will be to the west. Severe threat will increase but not enough to warrant anything other than a mention at this time.
Long term (Beyond 60 hr):
Trough will deepen and the cold front will stall and weaken in the early part of the week bringing a chance for showers and storms on Monday and Tuesday before slowly moving past the region. Will go high chance on Monday and Tuesday. Once confidence grows in the timing of the front and upper level support. Autumn weather will invade the area after the passage of the front through the end of the week.
Forecast:
Friday afternoon: 60% chance of storms with heavy rain possible at times. Precip .25 inches but higher in storms. High 86
Friday night: 40 % chance of showers and storms.. precip less than .1 inches
Saturday: 40 % chance of showers and storms through the night.. precip less than .1 inches High 89 low 72
Sunday: 50 % chance of showers and storms mainly before 10 pm.. precip .1 - .25 inches High 89 low 72
Monday: 40% chance of showers and storms after 2 pm High 85 low 72
Tuesday: 40% chance of showers and storms through the night. High 85 Low 72
Wednesday: Mostly cloudy in the morning partly cloudy in the afternoon High 81 Low 65
Thursday: Partly Cloudy High 79 Low 60
Review of RAH AFD: Need to watch for dry air on Saturday. Keep a good eye out on upper divergence as well. A lot of stuff to look at through with a full forecast. RAH breaks it up into several sections. Precip early next week may be some overrunning. When looking at theta e to determine position of front need to consider that part of the hold up is due to downsloping effect. So I need to look at the pressure field and wind direction to determine if front has passed.
Thursday, August 27, 2009
Thursday Aug 27
Past day verification and analysis: Low of 70 with no precip - I predicted a low of around 70 for the evening forecast/Thursday low... I'm off to a good start.
Synoptic analysis:
Upper level low in the SE will begin to shift eastward today. Chance of afternoon storms today as the dry stream of air lifts north of the region. Danny will approach the Outer Banks Friday afternoon/evening and potentially interact with upper level support to increase storm chances. A cold front will move through Sunday enhancing the chances for Thunderstorm activity. Moisture is limited but available with PW values exceeding 1.2 inches.
Near term (12 hr):
NAM is showing an increased chance of convection later this afternoon centered over the northern piedmont. SBCAPE has already exceeded 2500 J/Kg. Storms will be scattered and unorganized due to a lack of sufficient shear. The stream of dry air in the upper atmosphere has shifted to our north based on water vapor. Initiation of storms looks to be a weak pressure anomaly at the surface based on the latest RUC. This is currently located just west of Winston Salem. Severe winds due to downdrafts are possible this afternoon. NCAPE values are not too impressive but can't rule out small hail and weak downdrafts if storms develop. Will go with climatological chance PoPs for the triangle without mention of severe. Will lower temps slightly due to enhanced cumulus cloud cover this afternoon. No reason not to stick with persistence on the overnight low.
Short term ( 12 -36 hr):
In the short term concentration shifts towards the impact of the deep south upper level low and tropical storm Danny. Current guidance has Danny moving just east of the Carolina coast and northward toward Boston. 12z Nam has the track shifted slightly west. Although... I will strictly follow NHC/HPC guidelines for now. The interesting part is how Danny will interact with the upper low over the deep south which is forecast to shift east. The closed low will lift and become open toward the end of the short term. 500 mb vort max will approach late in the day on Friday. At the same time a zone of convergence could form from the juxtaposition of Danny and southerlies ahead of a low pressure in Indiana. The thinking is that a band of showers and storms will set up near the triangle due to all of these factors.... Therefore will go with greater than climatological chances of precip on Friday. Also, could see bands directly associated with Danny also effect the eastern piedmont. Will go with climatological temps despite southerly winds due to clouds associated with Danny. These clouds also might reduce available convective potential cenergy... but not enough to lower PoPs.
Long term (Beyond 36 hr):
The open wave in the deep south will lift out of the region and focus will shift toward a deepening upper level low near the great lakes which will eventually become closed. Latest model guidance is stronger and more transient with the upper low. The triangle will be under the right entrance region of the upper level jet associated with this closed low. A surface low will move down stream of the upper low and eventually become stacked. A relatively strong trailing cold front for this time of year will approach the region on Sunday afternoon. GFS theta e analysis shows the cold front not moving through until Tuesday afternoon (oh the agony). Therefore the GFS shows storms developing on Sunday and Monday. Not currently confident that the cold front will stall over the region on Monday therefore will only go with slight chance PoPs... but do feel confident that numerous storms will develop on Sunday to warrant likely PoPs. Will go above climatology on Saturday afternoon due to being in the warm sector, therefore enough instability should exist to warrant high chance. Will keep an eye on the severe threat on Sunday as shear and helicity will be enhanced due to better upper level support. Will keep temps at climatology due to increased cloud coverage. After cold front moves through expect dry and cooler conditions.
Forecast:
Wednesday afternoon: 30% chance of storms. Precip less than .1 inch except higher in storms. High 93
Thursday night: 30% chance of showers and storms before 10 PM. Low around 70.
Friday: 50% chances of storms mainly after 2 PM. 40 % chance of storms through the night. High 87 Low 72 precip .25 inches
Saturday: 30% chance of storms in the afternoon. High 88 low 71. precip less than .1 inches
Sunday: 60% chance of storms mainly after 2 pm. high 86 low 71. precip .3 inches
Monday: 30% chance of storms mainly after 2 pm. high 85 low 68. precip less than .1 inches
Tuesday: Mostly cloudy giving way to sun in the afternoon high 83 low 60
Wednesday: Clear and seasonably cool high 80 low 60
Review of RAH AFD: Near term: I took a look at the sounding but I missed the inversion layer in the mid atmosphere. It looks like that has a good chance to be overcome though. I'll be sure to look for that next time.
Synoptic analysis:
Upper level low in the SE will begin to shift eastward today. Chance of afternoon storms today as the dry stream of air lifts north of the region. Danny will approach the Outer Banks Friday afternoon/evening and potentially interact with upper level support to increase storm chances. A cold front will move through Sunday enhancing the chances for Thunderstorm activity. Moisture is limited but available with PW values exceeding 1.2 inches.
Near term (12 hr):
NAM is showing an increased chance of convection later this afternoon centered over the northern piedmont. SBCAPE has already exceeded 2500 J/Kg. Storms will be scattered and unorganized due to a lack of sufficient shear. The stream of dry air in the upper atmosphere has shifted to our north based on water vapor. Initiation of storms looks to be a weak pressure anomaly at the surface based on the latest RUC. This is currently located just west of Winston Salem. Severe winds due to downdrafts are possible this afternoon. NCAPE values are not too impressive but can't rule out small hail and weak downdrafts if storms develop. Will go with climatological chance PoPs for the triangle without mention of severe. Will lower temps slightly due to enhanced cumulus cloud cover this afternoon. No reason not to stick with persistence on the overnight low.
Short term ( 12 -36 hr):
In the short term concentration shifts towards the impact of the deep south upper level low and tropical storm Danny. Current guidance has Danny moving just east of the Carolina coast and northward toward Boston. 12z Nam has the track shifted slightly west. Although... I will strictly follow NHC/HPC guidelines for now. The interesting part is how Danny will interact with the upper low over the deep south which is forecast to shift east. The closed low will lift and become open toward the end of the short term. 500 mb vort max will approach late in the day on Friday. At the same time a zone of convergence could form from the juxtaposition of Danny and southerlies ahead of a low pressure in Indiana. The thinking is that a band of showers and storms will set up near the triangle due to all of these factors.... Therefore will go with greater than climatological chances of precip on Friday. Also, could see bands directly associated with Danny also effect the eastern piedmont. Will go with climatological temps despite southerly winds due to clouds associated with Danny. These clouds also might reduce available convective potential cenergy... but not enough to lower PoPs.
Long term (Beyond 36 hr):
The open wave in the deep south will lift out of the region and focus will shift toward a deepening upper level low near the great lakes which will eventually become closed. Latest model guidance is stronger and more transient with the upper low. The triangle will be under the right entrance region of the upper level jet associated with this closed low. A surface low will move down stream of the upper low and eventually become stacked. A relatively strong trailing cold front for this time of year will approach the region on Sunday afternoon. GFS theta e analysis shows the cold front not moving through until Tuesday afternoon (oh the agony). Therefore the GFS shows storms developing on Sunday and Monday. Not currently confident that the cold front will stall over the region on Monday therefore will only go with slight chance PoPs... but do feel confident that numerous storms will develop on Sunday to warrant likely PoPs. Will go above climatology on Saturday afternoon due to being in the warm sector, therefore enough instability should exist to warrant high chance. Will keep an eye on the severe threat on Sunday as shear and helicity will be enhanced due to better upper level support. Will keep temps at climatology due to increased cloud coverage. After cold front moves through expect dry and cooler conditions.
Forecast:
Wednesday afternoon: 30% chance of storms. Precip less than .1 inch except higher in storms. High 93
Thursday night: 30% chance of showers and storms before 10 PM. Low around 70.
Friday: 50% chances of storms mainly after 2 PM. 40 % chance of storms through the night. High 87 Low 72 precip .25 inches
Saturday: 30% chance of storms in the afternoon. High 88 low 71. precip less than .1 inches
Sunday: 60% chance of storms mainly after 2 pm. high 86 low 71. precip .3 inches
Monday: 30% chance of storms mainly after 2 pm. high 85 low 68. precip less than .1 inches
Tuesday: Mostly cloudy giving way to sun in the afternoon high 83 low 60
Wednesday: Clear and seasonably cool high 80 low 60
Review of RAH AFD: Near term: I took a look at the sounding but I missed the inversion layer in the mid atmosphere. It looks like that has a good chance to be overcome though. I'll be sure to look for that next time.
Tuesday, August 25, 2009
Wed. 8/26 Forecast
Past day verification and analysis: NA
Synoptic analysis:
Closed upper level low low pressure currently located over the deep south along with a surface high over the southern Apps will lead to dry warm conditions through today and into tonight.
Near term (12 hr):
A strong upper level low is centered near Mississippi. HPC has drawn a pair of high pressures along the southern Appalachians. These 2 features have combined to form subsidence leading to a warm dry environment. The air above 650 mb is extremely dry which can be seen on water vapor and current soundings out of GSO. Expect this pattern to continue through the night. Cloud cover over night should be minimal due to the subsidence and dry air. Also, expect the inversion layer to keep surface winds relatively calm.
Short term ( 12 -36 hr):
The warm dry pattern will continue in the short term with the upper level low slowly shifting eastward. However... models show a weak impulse entering the forecast region at around 0z Friday... which should enhance shower chances Friday. Moisture levels are marginal and neither the NAM nor the GFS are bullish with QPF so will go with only summer climatological chances for Friday afternoon. CAPE and associated convection appear to be limited due to afternoon cloud cover Friday afternoon. This implies surface temps on Friday will be lower then persistance by several degrees. If cloud cover is not a factor on Friday then expect a good chance of afternoon thunderstorms.
Long term (Beyond 36 hr):
The long term starts out messy as the upper level low shifts east and interacts with Tropical Storm Danny. NHC currently predicts Danny to move just off the North Carolina shore. CCW winds around Danny could interact with SW winds along a surface low in Tennessee.... which could create a zone of convergence Saturday afternoon... moisture is limited however. Will go chance PoPs Saturday afternoon. A closed low will set up later in the forecast period as Danny exits the region. The associated trough will deepen... expect impulses to ride along this trough enhancing the chances for precip later in the weekend and into early next week. The trough will hold on but dampen as the middle of the week nears. The timing of these impulses are anyones guess in the long range. A cold front will come through sometime during the day on Monday. After this a relatively strong high pressure will build in from the west. Will stick with chance pops through Monday with partly cloudy skies on Sunday. Highs will be slightly below climatology due to expected cloud cover associated with any impulses.
Forecast:
Wed night: Clear with a low around 70
Thursday: Sunny and hot.. High 95 low near 70
Friday: 30% chance of storms.. precip less than .1 inches.. High 85 Low 69
Saturday: 30% chance of storms.. precip less than .1 inches.. High 85 low 70
Sunday: 30% chance of afternoon storms.. precip less than .1 inches.. High 82 low 70
Monday: 30% chance of afternoon storms.. precip less than .1 inches.. High 82 low 70
Tuesday: Partly Sunny.. High 82 low 70
Synoptic analysis:
Closed upper level low low pressure currently located over the deep south along with a surface high over the southern Apps will lead to dry warm conditions through today and into tonight.
Near term (12 hr):
A strong upper level low is centered near Mississippi. HPC has drawn a pair of high pressures along the southern Appalachians. These 2 features have combined to form subsidence leading to a warm dry environment. The air above 650 mb is extremely dry which can be seen on water vapor and current soundings out of GSO. Expect this pattern to continue through the night. Cloud cover over night should be minimal due to the subsidence and dry air. Also, expect the inversion layer to keep surface winds relatively calm.
Short term ( 12 -36 hr):
The warm dry pattern will continue in the short term with the upper level low slowly shifting eastward. However... models show a weak impulse entering the forecast region at around 0z Friday... which should enhance shower chances Friday. Moisture levels are marginal and neither the NAM nor the GFS are bullish with QPF so will go with only summer climatological chances for Friday afternoon. CAPE and associated convection appear to be limited due to afternoon cloud cover Friday afternoon. This implies surface temps on Friday will be lower then persistance by several degrees. If cloud cover is not a factor on Friday then expect a good chance of afternoon thunderstorms.
Long term (Beyond 36 hr):
The long term starts out messy as the upper level low shifts east and interacts with Tropical Storm Danny. NHC currently predicts Danny to move just off the North Carolina shore. CCW winds around Danny could interact with SW winds along a surface low in Tennessee.... which could create a zone of convergence Saturday afternoon... moisture is limited however. Will go chance PoPs Saturday afternoon. A closed low will set up later in the forecast period as Danny exits the region. The associated trough will deepen... expect impulses to ride along this trough enhancing the chances for precip later in the weekend and into early next week. The trough will hold on but dampen as the middle of the week nears. The timing of these impulses are anyones guess in the long range. A cold front will come through sometime during the day on Monday. After this a relatively strong high pressure will build in from the west. Will stick with chance pops through Monday with partly cloudy skies on Sunday. Highs will be slightly below climatology due to expected cloud cover associated with any impulses.
Forecast:
Wed night: Clear with a low around 70
Thursday: Sunny and hot.. High 95 low near 70
Friday: 30% chance of storms.. precip less than .1 inches.. High 85 Low 69
Saturday: 30% chance of storms.. precip less than .1 inches.. High 85 low 70
Sunday: 30% chance of afternoon storms.. precip less than .1 inches.. High 82 low 70
Monday: 30% chance of afternoon storms.. precip less than .1 inches.. High 82 low 70
Tuesday: Partly Sunny.. High 82 low 70
This is a weather blog for the Triangle of North Carolina. This blog will contain a daily forecast along with an area forecast discussion. Links to forecasting maps and discussions will also be provided so that the viewers of the website can follow along with the discussion. Other random information will also be posted from time to time.
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