Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 08/03/19

National Weather Service Albany NY
1037 PM EDT Fri Aug 2 2019 .SYNOPSIS... Northern areas will be fair and chilly tonight, while southern areas will see an increase in cloudiness, with a chance of a shower or thunderstorm. Isolated to scattered showers and thunderstorms are expected from the Capital District and to the south and east Saturday mainly during the afternoon into the early evening hours. Fair and seasonable weather is expected for Sunday and Monday. && .NEAR TERM /THROUGH SATURDAY/... Updated at 1030 pm. Mid-to-upper level wave moving northeast from Pa and western NY is easily identified by satellite imagery late this evening. Cloud top temperatures have begun to warm with this system as of late this evening and radar loops have shown a clear weakening trend with convection that had been over central NY eariler in the evening. Latest CAMS including the 00z HRRR and NAM nest all indicate isolated to scattered coverage of showers moving east toward our area overnight with chc pops implied across much of the area by around 12z. Showers and storms may become heavier and a bit more widespread by early afternoon, especially to the south and east of Albany as the tail end of the wave interacts with an atmosphere destabilizing due to diurnal heating. Previous discussion is below. Updated at 8 pm. Mid-to-upper level wave associated with height falls and scattered showers over Pa and south central NY will move slowly east across the area through Saturday morning. The wave will bring scattered showers to our area, especially south of I-90 where weak southerly flow ahead of the wave will bring dew points back into the mid to upper 60s overnight. Showers will likely diminish in coverage for awhile late this evening with the loss of daytime heating, but should increase again toward daybreak Saturday as the wave approaches. A few rumbles of thunder could occur with any heavier showers later tonight as modest instability is forecast to persist through the night. Clouds will increase overnight, with lows ranging from the 50s in the Adirondacks, to the 60s elsewhere. As of 407 PM EDT, mostly sunny skies continue, except across the southern third of the forecast area where skies have become partly cloudy with cumulus bubbling up. Temperatures range from the 70s in the hill towns to low to mid 80s in the valleys. dewpoints are generally in the 50s with 40s across the southern Adirondacks. Winds are variable at 10 MPH or less. Weak shortwave over Ohio is producing showers and thunderstorms from the southern tier of New York, across Pennsylvania, to southern NJ and the Delmarva Peninsula. Expect showers to our southwest to slowly move northeast tonight while dissipating. Have slight chance to chance POPs over eastern Catskills. && .SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/... The surface high will shift off the southern New England coast tonight leading to a developing southerly flow. This southerly flow will advect moisture from the mid Atlantic States northeast ward into our area. There are showers and thunderstorms now over southern tier of New York and northeastern Pennsylvania, and these will move slowly northeast tonight while dissipating. Have included slight chance to chance POPS over southern areas for showers and isolated thunder. Tonight will not be as cool across the southern part of the area with clouds overspreading like a blanket. However, the southern Adirondacks, lake George area and souther Vermont will not see as much cloudiness, and have dewpoints in the 40s this afternoon, so they may see low temperatures around 50 with some upper 40s possible. It will be more humid on Saturday and a cold front will approach the region from the north. Heights will fall across the region and dew points are expected to rise into the 60s across much of the area with upper 60s into the mid Hudson Valley and northwestern Connecticut. Guidance is consistent indicating convection should fire up from Capital District and to the south and east where the greater instability will be with the higher dew points. Expecting isolated to scattered storms mainly during the afternoon into the early evening hours. The storms are expected to weaken and dissipate with loss of daytime heating. Expecting highs once again in the 80s with mid and upper 70s occurring above 1500 feet. The cold front will drop south across the region Saturday night and with its passage drier air will begin to filter in on a light northerly flow. Low chance POPs for additional showers with the cold front. Expecting lows in the mid 50s north to mid 60s south. On Sunday morning, the front may be pushing through the eastern Catskills, mid Hudson Valley and NW Connecticut. For now, slight chance POPs over easter Catskills for a Sunday morning shower. Expecting fair weather will lower dew points, more comfortable humidity levels and a nice northerly breeze. Temperatures expected to be cooler especially across the higher terrain of the southern Adirondacks and southern Green Mountains. Looking at highs in the lower to mid 80s up the Hudson River Valley and northwestern Connecticut with 70s above 1000 feet in the higher terrain of the southern Adirondacks and southern Green Mountains. High pressure will shift across the region Sunday night. It will be cooler with lows down in the 50s with 40s in the normally cold spots of the southern Adirondacks, southern Vermont and possible Berkshire County MA as well. && .LONG TERM /MONDAY THROUGH FRIDAY/... Fair and seasonable conditions to start the forecast period, followed be unsettled conditions for Tuesday-Friday, as a large upper level trough slowly digs across eastern Canada and the Great Lakes region. High pressure should allow for fair conditions Monday, with warm daytime temps in the lower/mid 80s in valleys, 70s across higher terrain areas, and seasonably cool nighttime lows in the 50s to lower 60s, with some upper 40s possible across portions of the southern Adirondacks and southern VT. As the aforementioned trough initially digs into the Great Lakes region, a surface front approaching from the west should bring increasing chances for showers and thunderstorms Tuesday into Wednesday, with best chances associated just ahead of the front and/or with any pre-frontal boundaries. It will be warm and more humid ahead of the front, with highs mainly in the 80s for valleys, 75-80 across higher elevations. Overnight lows may be somewhat elevated due to cloud cover and higher humidity levels, with mainly 60s for lower elevations, and 55-60 across higher terrain. For Thursday into Friday, weather becomes a bit more nebulous, depending on how far south and east additional shortwave energy rotates around the deepening upper level trough. Showers and thunderstorms will be mainly diurnally driven during this time period, further enhanced with the approach/passage of any stronger upper level impulses. Temperatures Thursday-Friday may be a bit cooler due to more clouds, some showers and colder air aloft, with highs mainly in the mid 70s to lower 80s, and overnight lows in the 50s to lower 60s. && .AVIATION /03Z SATURDAY THROUGH WEDNESDAY/... An isolated shower over Ulster county early this evening will likely weaken and is not expected to affect the POU TAF site. VFR conditions will continue through most of the night, however increasing amounts of moisture may bring some MVFR cigs and vsbys toward daybreak especially at POU and PSF. Scattered showers will also develop across the area late tonight and continue into Saturday as increasing moisture interacts with a weak upper-level wave of low pressure moving east across the area. Some stronger thunderstorms may develop Saturday afternoon with the best chance being at PSF/POU. Winds will be variable at speeds less than 10 kts through Saturday, except stronger near any thunderstorms Saturday afternoon. Outlook... Saturday Night: No Operational Impact. NO SIG WX. Sunday: No Operational Impact. NO SIG WX. Sunday Night: No Operational Impact. NO SIG WX. Monday: No Operational Impact. NO SIG WX. Monday Night: No Operational Impact. NO SIG WX. Tuesday: Moderate Operational Impact. Chance of SHRA...TSRA && .FIRE WEATHER... Northern areas will be fair and chilly tonight, while southern areas will see an increase in cloudiness, with a chance of a shower or thunderstorm. Isolated to scattered showers and thunderstorms are expected from the Capital District and to the south and east Saturday mainly during the afternoon into the early evening hours. Fair and seasonable weather is expected for Sunday and Monday. Maximum relative humidity values tonight are forecast to be 85 to 100 percent. Minimum values Saturday will be in the mid 40s to mid 50s. Saturday night RH recovers again to 85 to 100 percent. && .HYDROLOGY... Isolated to scattered showers and thunderstorms are expected from the Capital District and to the south and east Saturday mainly during the afternoon. Fair weather is expected for the second half of the weekend and to start the new work week. The weather will then turn unsettled beginning on Tuesday as low pressure approaches and moves across the region. Any thunderstorm will be capable of producing locally heavy downpours. River flooding is not anticipated at this time. Please visit our Advanced Hydrologic Prediction Service /AHPS/ web page for specific area rivers and lakes observations and forecasts. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. MA...None. VT...None. && $$ SYNOPSIS...SND NEAR TERM...SND/MSE SHORT TERM...SND LONG TERM...KL AVIATION...MSE FIRE WEATHER...SND HYDROLOGY...SND
Area Forecast Discussion
National Weather Service Charleston SC
1026 PM EDT Fri Aug 2 2019 .SYNOPSIS... A weak coastal trough will persist through Saturday before dissipating. A front will then stall near the area early next week. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... Late this evening: No change to the forecast thinking for the rest of the night. However, the last few runs of the HRRR and RAP are now taking the offshore wave, and the main area of showers and thunderstorms associated with it, just a bit further offshore. The result is that these newer runs would now keep most land areas dry. On the other hand the new NAM still puts quite a bit of activity along and just inland of the coast. With the late evening update the highest rain chances have been shifted a bit further east, but it will be a close call for where showers and thunderstorms set up. That will be the main forecast challenge overnight. Early this evening: There wasn`t much convection this afternoon across the forecast area as cloud cover and morning rainfall prevented much, if any, destabilization. However, we are situated within a very moist airmass with precipitable water values on the order of 2-2.2 inches, and the onshore flow around the nearby surface trough is producing enough convergence for showers to develop along the Georgia coast. Through the evening and the rest of the overnight, models are in pretty good agreement showing a weak surface wave off the east coast of Florida pushing northward into the waters of the forecast area. As it does, showers and thunderstorms are expected to increase in coverage over the waters and then begin to rotate toward the coast and push inland. Rain chances steadily increase in this manner, with the best chance for rain to occur as we approach sunrise and through the mid morning along the South Carolina coast. Overall, the rain chances we had in place look good and no significant changes were made. Fortunately, it looks like the peak of showers and thunderstorms will be well after the high tide tonight, so that should lessen any freshwater flooding concerns. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/... A coastal trough will slowly move northeast along the coast on Saturday. Scattered to numerous showers along with a few thunderstorms are expected during the day, especially across southern SC and coastal GA. PWATs will be above 2.2" along coastal areas, thus locally heavy rainfall will be possible. On Sunday the surface trough will pull away from the area, however a weak upper trough lingering to the west will still allow for at least scattered showers and tstms. The upper trough will drift to the east on Monday, pushing a weak surface front toward the area. Moderate instability and a moist airmass will support scattered to numerous showers and tstms, especially in the afternoon. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... Mid-level troughing will persist over the East Coast. At the surface, weak troughing will prevail inland while high pressure is over the Atlantic. Expect the typical afternoon showers/thunderstorms with seasonal temperatures. && .AVIATION /03Z SATURDAY THROUGH WEDNESDAY/... A tricky forecast period is on tap through 00z Sunday. At KCHS, VFR conditions are expected to prevail through the evening. Then around after midnight, the chance for showers and thunderstorms goes up as well as the potential for MVFR or lower ceilings. Overall, the worst conditions are expected generally in the 09-15z time frame. We introduce prevailing MVFR ceilings at 05z, lowering them close to IFR by 09z. Confidence is too low in IFR at this point to include in the forecast. Thunder is certainly possible, and has been included in a TEMPO group from 10-13z. After mid-morning, overall confidence is low but we expect there to be a lull in shower and thunderstorm activity with a general improvement in conditions with VFR returning by early afternoon. At KSAV, MVFR ceilings are already impacting the terminal, though probably on a TEMPO basis this evening. Then late tonight, rain chances increase as showers and thunderstorms develop offshore and attempt to push onshore. Have timed prevailing MVFR ceilings in at 04z with showers. Could see a period of IFR ceilings closer to sunrise, but confidence is too low to include at this time. Expecting improving conditions by late morning with a return to VFR by midday or early afternoon. Extended Aviation Outlook: Occasional ceiling and/or visibility restrictions are possible due to showers and tstms. && .MARINE... Tonight: Mainly east winds, shifting to more southeast late, as a trough approaches from the south. Speeds should peak in the 10-15 kt range with seas up to 4 ft, highest near the Gulf Stream. Friday through Tuesday: Atlantic high pressure will remain the dominant feature Saturday through the middle of next week, along with a few weak surface troughs meandering through the waters. No headlines are expected. && .TIDES/COASTAL FLOODING... Tides are reaching their peak now and will fall just shy of warning criteria at both Charleston Harbor and Fort Pulaski. Will leave the warning up until tides fall below 7 ft and 9.2 ft respectively. The combination of astronomical and meteorological influences will continue to generate elevated tides this weekend. The Saturday evening high tide is forecasted to reach Coastal Flood Advisory levels for the entire coast while the Sunday evening high tide may reach Coastal Flood Advisory levels for only the Southeast SC coast. Additionally, if heavy rainfall occurs around the time of high tide, this will exacerbate the flooding, especially for the Charleston Peninsula. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...Coastal Flood Warning until 1 AM EDT Saturday for GAZ117-119- 139-141. SC...Coastal Flood Warning until 1 AM EDT Saturday for SCZ048>051. Coastal Flood Advisory until 1 AM EDT Saturday for SCZ052. MARINE...None. && $$ NEAR TERM...BSH SHORT TERM...JRL LONG TERM...MS AVIATION...BSH/JRL MARINE...RJB/JRL TIDES/COASTAL FLOODING...
Area Forecast Discussion
National Weather Service Duluth MN
628 PM CDT Fri Aug 2 2019 .SHORT TERM...(This evening through Saturday night) Issued at 304 PM CDT Fri Aug 2 2019 A stalled out frontal boundary was located along the International Border early this afternoon with high pressure in place to the south of Lake Superior. Isolated to scattered showers and thunderstorms were seen across northeast Minnesota and this activity is expected to continue for the remainder of the afternoon hours before diminishing during the early evening hours. Storms have been firing in an uncapped airmass characterized by 1000-2000 J/kg of CAPE and shear under 15 knots. These storms have been pulse-y in nature and one cell near Silver Bay featured nickel-sized hail. Given the lack of shear, expecting that nickels will be about the best these storms can do. Winds through the column are also extremely weak, so not expecting much in wind gusts from the storms either. Used the HRRR to highlight slightly higher POPs this afternoon along with observational trends. This activity is expected to drift southeast into this evening with dry conditions expected for the overnight hours as lows cool into the middle 50s to middle 60s. The boundary will remain in the area for tomorrow, leading to another afternoon of isolated to scattered showers and thunderstorms. Without an organized mechanism for convergence, it is difficult to try and hone in on an area that will see the best chance Saturday afternoon. Since today`s plan with the lake breeze leading to initial convection and outflow boundaries thereafter is not really panning out, opted to blanket the area with low POPs and let later shifts refine this area based on satellite, radar and CAM trends. Conditions look virtually the same for tomorrow with 1000-2000 J/kg of CAPE along with shear under 20 knots. This will lead to pulse-type airmass storms that may produce sub-severe hail and heavy rainfall, but not much else. This activity will again be diurnally driven, so a weakening trend is expected during the early evening hours leaving dry conditions for overnight. Highs Saturday will top out in the middle 70s to middle 80s with lows in the middle 50s to middle 60s. .LONG TERM...(Sunday through Friday) Issued at 304 PM CDT Fri Aug 2 2019 Sunday through Monday we have a cold front that slowly slides through the area, which is associated with an upper level low and trough axis that moves through Manitoba and into Ontario through this period. The better dynamics will be north of the the Northland, but we are still looking at a period of chances for showers and thunderstorms both days, focused mainly along and ahead of the front as it moves through the area. High temperatures on Sunday to remain in the 80s, but then as the front moves through, it will become cooler on Monday, with highs only in upper 70s to low 80s, at least in part due to increased cloud cover. The upper low will still be in the vicinity on Tuesday, even as the cold front shifts off to the southeast of the area. This will leave us with some diurnally driven showers and thunderstorms in the cyclonic flow, and am carrying some small chances for showers and storms, mainly during the afternoon and evening hours. Temperatures to remain on the cooler side, with highs in the mid to upper 70s. The latter half of the work week the upper level pattern keeps us in northwest flow aloft, with the upper low from earlier in the week over Hudson Bay or even Quebec, and a ridge over the Rockies. This will produce some small chances for showers and thunderstorms with weak shortwaves sliding through that flow, but have poor confidence in the timing and track of such shortwaves and have kept pops to slight chance or lower through Friday. Temperatures should be a little cooler than normal, but not unusual for this time of year, with highs Wednesday through Friday in the 70s for most locations. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 629 PM CDT Fri Aug 2 2019 As isolated showers and storms dissipate early this evening across northeast Minnesota and northwest Wisconsin, skies will at least partially clear out, especially at HIB and INL. Fog is expected to develop, possibly reducing visibility to less than a mile at DLH and HIB towards Saturday morning. On Saturday, fog will burn off by mid-morning with VFR conditions expected to prevail through the day with a mix of sun and clouds. Isolated showers and storms are again possible, but left out any mention of precip in this set of TAFs due to very low confidence in whether any terminal may see precipitation. Winds very light at around 5 knots or less and variable in direction through the forecast period, nearly calm at times overnight. && .MARINE... Issued at 304 PM CDT Fri Aug 2 2019 Scattered thunderstorms over the area this afternoon will continue to move out over Lake Superior, and bring locally higher winds and waves, along with some lightning and small hail with the stronger storms. Otherwise, southwest to west winds today near or less than 10 knots are expected to turn to the northeast late tonight or early Saturday, and slowly increase through the day. These winds may increase to around 15 knots in the southwest arm of the lake in this northeast flow, and depending on gusts we may need a small craft advisory for a few hours in the afternoon. The east to northeast winds are expected to continue into Sunday, but generally remain less than 10 knots. && .PRELIMINARY POINT TEMPS/POPS... DLH 61 80 59 84 / 40 40 10 20 INL 58 85 62 84 / 10 30 10 50 BRD 62 84 63 85 / 10 30 0 20 HYR 60 84 59 84 / 20 30 10 10 ASX 61 80 59 86 / 40 20 10 20 && .DLH WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. LS...None. && $$ SHORT TERM...BJH LONG TERM...LE AVIATION...JJM MARINE...LE
Area Forecast Discussion
National Weather Service Hastings NE
725 PM CDT Fri Aug 2 2019 .SHORT TERM...(This evening through Saturday) Issued at 353 PM CDT Fri Aug 2 2019 Aloft: Upr-air data from RAOBs and aircraft and RAP tropopause analyses showed that the flow over the CONUS was dominated by a large subtropical high over NM with a ridge extending into the Canadian Prairies. Trofs were along the Pac NW coast and along the Appalachians. Anticyclonic NW flow was over NEB/KS. A wk mid-lvl shrtwv trof extended from ND-KS. This trof will diminish further as rounds the high into the lwr MS Vly by 00Z/Sun. Surface: High pres was over the GtLks. A barely noticeable stationary front extended acrs the Gulf Coast states to wk low pres along the KS-OK border. Another wk low was over SD. This low will dissipate tonight while the KS-OK low gradually sinks into Nrn TX by 00Z/Sun. Meanwhile...the wk GtLks high will gradually shift to the W and extend into NEB. Rest of this afternoon: Partly to mostly cldy. The mdls hv been struggling with the nebulous forcing. The main concern on this shift has been the persistent low-echo-centroid convection affecting Valley county with flash flooding. The echoes hv been very persistent. 88D estimates pockets of 4-8" may hv occurred. We won`t know for sure until the gauge reports come in. We hv received reports of water over county roads. PWAT is around 2". These are incredibly efficient rainers with warm rain processes dominating. Can`t rule out isold shwrs popping up elsewhere...but despite the lack of a cap...the lack of forcing may keep much from happening outside of what`s already in progress. Tonight: Partly cldy during the eve. Can`t rule out isold shwrs and possibly a tstm or two. Somewhat begrudgingly left a mention of precip in the fcst...but believe most locations should remain dry. Conds are fvrbl for fog and low stratus to reform. MAV MOS has been insistent for the last 5 runs that widespread fog will form with vsbys in some areas 1/4 mi or less. We may need to issue a Dense Fog Advy. Sat: A foggy start for most if not all the area. It could be dense. Skies should eventually become partly cldy...but as it erodes from the edges...there could be a swath that remains mostly cldy for much of the day. Did maintain a mention of precip...but it will probably be dry. .LONG TERM...(Saturday night through Friday) Issued at 353 PM CDT Fri Aug 2 2019 Aloft: Moderately-amplified anticyclonic NW flow Sun will deamplify Mon as a fairly potent low mvs thru the Canadian Prairies. This will cause heights to fall and cyclonic WNW flow over NEB/KS as the subtropical high gets suppressed and shoved back into the W a bit. The flow will become less cyclonic mid-late next wk...but remain from the WNW. Surface: A cool front associated with the Canadian Prairies low will move thru Mon. Another cool front is fcst to mv thru Thu. In the interim...wk high pres. Temps: averaging a little cooler than normal. Pcpn: Isold tstms will be psbl Mon with the FROPA. Thereafter... the mdls are suggesting isold tstms here and there...but predictability and confidence are extremely low. Overall...the chance of rain is not good. Most locations will remain dry. && .AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Saturday) Issued at 719 PM CDT Fri Aug 2 2019 Significant wx: IFR CIGs/VSBYs likely. Tonight: Mixed VFR/MVFR/IFR conditions next few hrs, with VFR/MVFR the most prominent through 04Z. CIGs will deteriorate around 06Z with eventually some fog developing by 09Z, which will probably fall to 1/2 to 1 mi through dawn. Winds will be lgt out of the ESE before going lgt and vrbl late. Confidence: CIGs - high, VSBYs - medium. Saturday: IFR to MVFR. IFR CIGs/VSBYs expected to start the day with gradual improvement by mid to late morning. Should see primarily MVFR CIGs for the aftn, but VFR isn`t out of the question. Winds will be SE around 5-10kt. Confidence: Medium. && .HYDROLOGY... Issued at 353 PM CDT Fri Aug 2 2019 We need to watch the N Loup Rvr Basin as svrl inches of rain fell this aftn. That water will be working its way down thru Valley/ Greeley/Howard counties. Water lvls will be rising for sure. We may need to issue Areal Flood Wrngs for the N Loup Rvr and the creeks that drain into it. .GID WATCHES/WARNINGS/ADVISORIES... NE...None. && .GID WATCHES/WARNINGS/ADVISORIES... NE...None. KS...None. && $$ SHORT TERM...Kelley LONG TERM...Kelley AVIATION...Thies
Area Forecast Discussion
National Weather Service Paducah KY
747 PM CDT Fri Aug 2 2019 .UPDATE... Issued at 744 PM CDT Fri Aug 2 2019 Updated the public forecast to add in some isolated showers and thunderstorms in a few locations for the next couple of hours. Recent HRRR data indicates that the convection moving west from Bowling Green Kentucky will eventually spread back into our Pennyrile counties before dissipating late this evening. Also a rogue shower has developed out of an area of agitated cu in Hamilton county Illinois. A few more will be possible in the zone roughly from Carmi to Mt Vernon Illinois in the next hour or two. UPDATE Issued at 616 PM CDT Fri Aug 2 2019 The AVIATION section has been updated for the 00Z TAF issuance. && .SHORT TERM...(Tonight through Sunday night) Issued at 232 PM CDT Fri Aug 2 2019 Surface high pressure centered over Lake Michigan this afternoon is ever so slowly losing its grip on the region. The result is an increase in cumulus clouds and an uptick in humidity levels, at least across the eastern half of the region. A few very isolated showers briefly popped up in Todd County Kentucky early this afternoon. A small chance for isolated convection will remain possible this afternoon over western Kentucky. Guidance has come into better agreement depicting an uptick in convection for Saturday afternoon. This looks to be mainly across the southern half of the region, coinciding with an increase in low to mid level moisture associated with weak energy in the broad trough across the southeast U.S. Overall coverage should still be rather low though. Slight chance PoPs remain in place mainly across western Kentucky on Sunday, as the better moisture appears to get shoved a little further south. Temperatures remain seasonably warm in the upper 80s for highs and upper 60s for lows through the weekend. .LONG TERM...(Monday through Friday) Issued at 232 PM CDT Fri Aug 2 2019 The medium range models and the GEFS/ECENS appeared to be in reasonable agreement for the extended forecast period, with finer details a bit harder to pin down. The country will continue to be under a persistent ridge west/trof east mid/upper pattern. This will keep the PAH forecast area under northwesterly flow aloft through the period. At this time, the first half of next week appears drier than the second half in the models. One of the more persistent signals for possible pcpn will be sometime in the middle of next week, associated with one or more shortwave impulses embedded in the increasingly cyclonic northern stream flow. The presence of this energy should result in some mid level height falls in our region as the western ridge is nudged westward. A weak surface reflection (cold front) may approach as early as Tue. The initialization blend yielded Tue night as a peak time for PoPs (but generally no more than a 1 out of 3 chance), fading off to the east on Wed. The next pcpn signal appeared to be on Day 7 (Fri) when possible MCS activity may get going in the northern Plains and head southeastward into our region. The general forecast of limited probability of showers and tstms will probably hold, however the timing and intensity of activity next week will remain quite changeable. While surface dewpoints should stay in the range of 65 to 70 across the region, high temps should start out around 90, with lows around 70. The latter half of the week is forecast to be cooler by just a few degrees at most. && .AVIATION... Issued at 616 PM CDT Fri Aug 2 2019 It appears that the isolated showers over west Kentucky have given up for the evening. Clear and nearly calm conditions may lead to some fog development late tonight. As has been the case lately, KMVN will have the greatest chance at fog late tonight, and cannot rule out more IFR or lower conditions with mainly MIFG. Not sure about KCGI. Based on cross-over temperatures they should not repeat the MVFR fog from this morning. Guidance advertises a return of lower clouds from the south late tonight into Saturday morning. Any ceilings should be VFR, but a brief MVFR ceiling cannot be ruled out at KCGI from midday through mid-afternoon with a rather thick cu field expected. Isolated SHRA/TSRA will be possible again in the afternoon, but expected coverage is too low to mention in the forecasts as this time. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...None. MO...None. IN...None. KY...None. && $$ UPDATE...DRS SHORT TERM...SP LONG TERM...DB AVIATION...DRS
Area Forecast Discussion
National Weather Service Blacksburg VA
1153 PM EDT Fri Aug 2 2019 .SYNOPSIS... An old frontal boundary will combine with upper level disturbances to generate showers and thunderstorms across the Appalachians and central mid Atlantic region into the weekend. The boundary will continue to weaken and erode Sunday through Tuesday. && .NEAR TERM /THROUGH SATURDAY/... As of 845 PM EDT Friday... Convection has been much less this evening with most of the area in an area of relative weak instability on the cool side of the surface front along the far southeast periphery of the CWA. However have seen a few showers/storms develop near the boundary across the piedmont where likely tripped off via a passing outflow boundary seen on radar. These again not moving much and expect may see added development off outflow past dark espcly given a weak axis of instability over eastern sections and moisture convergence to the south. Latest short term models tend to fade these showers out shortly, while some including the latest HRRR show redevelopment of shra/tsra back toward the Blue Ridge/Roanoke through midnight within the light easterly flow. Therefore keeping in some low pops across eastern/southern sections for another few hours before cutting to mainly fog/stratus during the early morning hours given combo of clearing and weak upslope flow. Lows mainly in the 60s again per dewpoints in the moist 60s to lower 70s this evening. Previous update as of 640 PM EDT Friday... Sent a quick update to lower pops espcly across central sections where seeing little in the way of showers given only weak instability and support aloft. Also edged down coverage over the far west where have been worked over with mainly chance coverage for now elsewhere through the evening. Also lowered temps some in the southwest per cooling from heavier downpours from late this afternoon. Otrw just some other adjusts for clouds and to cut back on QPF this evening given less shower coverage than earlier expected. Previous discussion as of 318 PM EDT Friday... An upper trough axis will remain across the Appalachians this afternoon into Saturday. The combination of mid-level vorts, solar heating, orographic lift and low level boundaries will create scattered showers and thunderstorms this afternoon into tonight. The SPC mesoscale analysis at 18z indicated CAPEs from 1000-2000 J/KG and sfc based LIs around minus 2 to minus 4. The namnest, hrrr and HiResW-arw-east showed the best chance for convection along the southern mountains. Some of storms could contain heavy rain with precipitable water values in the 1.5 to 2.0 inch range and light steering flow. Cell mergers or outflow boundary enhancement may help intensify storms. An isolated strong to severe pulse thunderstorm is possible with damaging winds and hail. Decided not to post any flash flood watch because of forecasted limited coverage of heavy rains. Flash Flood guidance was below 2 inches in portions of western Greenbrier County, from parts of the New River Valley down into Smyth and Tazewell Counties, and around Lynchburg. Elsewhere FFG was fairly high above 2 inches. Areas of low clouds and fog will develop tonight into Saturday morning. Low temperatures tonight will range from the upper 50s in the mountains to upper 60s in the piedmont. Upper level troughiness will continue across our region on Saturday. Scattered showers and thunderstorms will form Saturday afternoon into Saturday evening. The Day 2 Convective Outlook keep us in general thunderstorms. There is no real change in the airmass expect for the mid-level temperatures being a touch warmer. High temperatures on Saturday will vary from the lower 70s in the mountains to the mid 80s in the piedmont. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... As of 318 PM EDT Friday... Broad trough remains in place, though airmass remains virtually unchanged. Front situated south of us, but a series of upper shortwaves will keep threat of showers and thunderstorms going into Monday, with the best chance during the afternoon/evenings. Temps still running close to normal for early August. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... As of 220 PM EDT Friday... Broad trough appears to amplify somewhat midweek pushing a cold front across our area Thursday. Appears a lull in convection as high pressure overhead, though airmass remains sub-tropical so not out of the question to have isolated storms. Better forcing arrives Wed-Thu as the front approaches with 5h heights falling. The models differ on how far south the front gets, but appears could see drier/lower humidity toward Friday. && .AVIATION /04Z SATURDAY THROUGH WEDNESDAY/... As of 650 PM EDT Friday... VFR conditions with localized MVFR/IFR possible in areas of low clouds and scattered convection this evening. Coverage of any lingering showers and thunderstorms will then diminish after sunset with areas of lower clouds and fog developing overnight. Some solutions hang onto added showers along the Blue Ridge overnight but too iffy to include mention attm. Ceilings will be lowering to IFR/MVFR across the area after midnight. Areas of fog will develop overnight especially in the valleys, as well as locations that received afternoon rainfall, and perhaps along the Blue Ridge per easterly flow. KLWB has the best chance for LIFR/IFR fog overnight into Saturday morning. Morning low clouds and fog will lift by afternoon return most locations to VFR conditions although low clouds/fog may hang in across eastern sections until midday. Widely scattered showers and thunderstorms will develop Saturday afternoon resulting in brief sub-VFR, but appear too sporadic to include mention in any of the Taf locations for now. .Extended Aviation Discussion... A weak boundary will remain close to the region through the end of the weekend. Scattered showers and thunderstorms with periods of sub-VFR ceilings can be expected through Sunday or Monday with coverage becoming less by Tuesday. This pattern will also result in MVFR or lower clouds and MVFR fog due to moist low levels, especially at night. Showers and thunderstorms may develop again Wednesday with the best chances in the northwest. && .EQUIPMENT... The NOAA weather radio at Lynchburg VA remains off the air tonight perhaps due to a surge with a lightning strike Thursday night. Technicians will continue to work to find the problem over the next couple of days although the time of restoration is unknown at this point. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...AMS/KK NEAR TERM...JH/KK SHORT TERM...WP LONG TERM...WP AVIATION...AMS/JH/KK EQUIPMENT...JH