Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 05/31/17

Area Forecast Discussion
National Weather Service Wakefield VA
1006 PM EDT Tue May 30 2017 .SYNOPSIS... A series of upper disturbances will move across the area today through tonight. A cold front approaches from the northwest Wednesday and tracks across the Mid-Atlantic region on Wednesday night. High pressure rebuilds over the area for the latter half of the week. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... No major changes necessary to the previous forecast. Did raise PoPs a bit over the Northern Neck/Middle Peninsula for an area of strong tstms this eveng, but mainly just up to a slight chance of rain elsewhere. Previous Discussion... Latest wx analysis reveals weak low pressure over South Central VA, with a quasi-stationary frontal boundary draped from the VA/NC border back into SE TN/N GA/AL. Aloft, deep occluded cyclone continues to spin over Central Ontario. Mid-afternoon regional radar mosaic showing a narrow line of showers, mainly along and north of the aforementioned boundary in the southeast into W SC. To the north, numerous clusters of storms have fired across W PA/NY State...along and ahead of the front. Visible Sat imagery showing partial clearing/thinning clouds back in the E VA Piedmont west of RIC. Continue to lean on the CAMs for the balance of the aftn/night, with the time-lagged HRRR and to a lesser extent the RAP showing a good handle on actual radar coverage thus far. Showers and storms will continue to fire to our north, along and ahead of the cold front. Expect a few isolated showers/storms will approach northern parts of our area by late this afternoon. Given lower PW/Theta-e values farther north, expect areal coverage will remain low, isolated to widely scattered at most. However, orientation of MLCAPE of ~1500 j/kg (750-1000 j/kg DCAPE) with 40-50 KT of Deep layer shear across the north would portend to a convective environment supportive of multi-cell clusters, with some supercell potential also present. SPC continues Day 1 Slight Risk just north of our local area, with all but the strongly-capped Lower Eastern Shore in a Marginal Risk Area. HWO mention is mainly along and north of RIC-Williamsburg line for the afternoon and evening, with damaging winds and large hail the primary hazards. Farther south, lower shear values and lingering clouds through the day (PW ~1.75" across the SE) have kept a lid on additional convective development thus far. That said, do expect convective development once again late this aftn and early evening across the Carolinas, sliding NE across E NC into South Central/SE VA from mid-evening through the early morning hours Wed. Given aforementioned stable marine layer across the Eastern Shore, have again held out thunder mention over the Eastern Shore, despite some modest elevated instability by early evening. Deep layer shear diminishes with time tonight, and therefore expect that activity across the north wanes steadily with loss of heating. As referenced above, shearing/dampening shortwave approaching from the SW argue for lingering a 30-40 POP into the overnight across the southeast. Sky cover will remain partly to mostly cloudy with stratus/patchy fog once again late. Early morning lows mainly in the 60s. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY/... An upper level trough will sharpen over the Great Lakes Wednesday pushing the surface cold front toward the local area from the interior northeast. 12z suite of guidance is once again a bit quicker with the frontal passage Wed, which yields a solution which leans toward a more active period of convective development Wednesday aftn and evening, owing to the combination of increased low-level moisture and stronger SW (rather than W) flow aloft. 30-40 POPs have been maintained in anticipation of scattered showers and T-Storms developing and pushing across the area Wed aftn/night. Otherwise, look for highs Wednesday in the upper 70s/around 80 along the coast, low to mid 80s inland. The mid-level trough axis will shunt surface cold front across the area Wednesday night, with POPs dropping off early across the piedmont, and after midnight mainly along and E of I-95 as the front clears the coast late Wed night. Post-frontal W-NW flow and surface high pressure building from the west should combine to yield a cooler/drier forecast for Thursday. After early morning lows in the upper 50s to mid 60s, highs Thursday should rise in the low 80s inland, with mid to upper 70s for the Lower Ern Shore and along area beaches. Thursday night and much of Friday appear to remain dry. Have gone with a slight to low end chance POP for some pulse convection SW sections (Tri-Cities toward the I-85 corridor) on Friday aftn as with developing low-level return flow. Otherwise, slightly warmer with highs in the mid 80s inland, in the u70s to around 80 along the coast. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... Latest models now somewhat slower and farther north with a frontal boundary placement over the weekend. Data now suggests boundary stalls to the N across northern Va with several impulses riding along it. The parent low tracks northeast into New England early next week with the trailing cold front crossing the region Monday. Upper level energy progged to rotate around this system into Tuesday. Despite the synoptic difference from yesterday, result won`t change much from previous thinking. Upshot will be for periods of showers/T-Storms through the period. Given the timing uncertainty, will keep pops capped at chc for now. Slight chc Tuesday. Highs sat 80-85, upr 70s-lwr 80s Sun and Mon, mid to upr 70s Tue. Lows in the mid-upr 60s except upr 50s to mid 60s Tue. && .AVIATION /02Z WEDNESDAY THROUGH SUNDAY/... KSBY is expected to remain locked into LIFR/IFR CIGS through Wednesday morning given persistent onshore flow. Elsewhere, am anticipating potential for MVFR to IFR conditions at KRIC around sunrise. Have indicated this in the KRIC TAF. Elsewhere, conditions expected to remain VFR overnight with light winds. Conditions improve at KRIC/KSBY later Wednesday morning as winds turn to the southwest ahead of a stronger cold front. OUTLOOK...There will be a chance for thunderstorms late Wednesday afternoon and evening. A cold front crosses the area Wednesday night and a dry day is expected Thursday as high pressure settles over the Mid Atlantic States. The high slips off the coast Friday and scattered showers and thunderstorms are indicated for the weekend as a slow moving cold front approaches from the northwest. Patchy fog will be possible within a few hours of sunrise each morning. && .MARINE... No headlines expected overnight as SE winds become S-SW at 10 KT or less. Seas avg 3-4 ft. The next cold front approaches the region Wed as south winds incrs to 10-15 knots. The front pushes across the waters late Wed night. Height rises and modest cold advection behind the front result in a wind shift to the N then NE but expect speeds to remain just below SCA levels. High pressure slides offshore Thursday night/Friday with flow returning to the south. The next front crosses the waters Saturday night. && .TIDES/COASTAL FLOODING... Onshore flow/swell and high astronomical tides have resulted in elevated water levels along the Bay and tidal rivers. Based on the latest data, decided to upgrade the Ches Bay side of the Lwr MD eastern shore to a coastal flood advisory through 12Z. Levels should reach minor flooding levels at Bishops Head for both this evenings and early Wed morning high tide cycles. Otw, additional statements will likely be needed for the middle Ches Bay as levels there reach action stage for tonight`s high tide cycle. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...Coastal Flood Advisory until 8 AM EDT Wednesday for MDZ021>023. NC...None. VA...None. MARINE...None. && $$ SYNOPSIS...MAM NEAR TERM...MAS/MAM SHORT TERM...AJZ/MAM LONG TERM...MPR AVIATION...LSA MARINE...JDM/MPR TIDES/COASTAL FLOODING...
Area Forecast Discussion
National Weather Service Burlington VT
803 PM EDT Tue May 30 2017 .SYNOPSIS... Large upper level low pressure across central Canada will pivot slowly east through the end of the week, driving a series of weak frontal systems across the area. As a result expect a near daily threat of showers, including scattered thunderstorms on Wednesday, a few of which may trend strong. Temperatures will remain near late spring norms throughout the seven day forecast period. && .NEAR TERM /THROUGH WEDNESDAY NIGHT/... As of 727 PM EDT Tuesday...Evening forecast remains in good shape with widespread showers from the Adirondacks eastward quickly exiting within the next few hours. Still monitoring a line of convection west of the St. Lawrence Valley that may clip Ogdensburg to Massena from 00-01Z but the loss of daytime heating has kept these storms relatively in check with no severe expected. Beyond midnight we should be looking at a quiet night with mild lows in the 50s and perhaps some areas of patchy fog. Previous Discussion... An active early evening still expected across the area as a distinct shortwave trough swings through the St. Lawrence Valley, driving numerous showers and a few thunderstorms, a few of which may be strong. A marine- modified airmass has penetrated quite far west this afternoon, covering all of VT and into the Adirondack Mountains where low level flow remains backed to south/southeasterly. A narrow instability axis extending from central New York north-northeast into the SLV and far western Dacks has developed to the immediate west of the marine airmass and it is in this small area where the potential for any stronger storms will exist through late afternoon/early evening. Please note Severe Thunderstorm Watch #299 remains intact to our immediate south and west through 00Z. CAM output has largely handled today`s activity quite well, especially the HRRR and have leaned heavily in it`s direction in regard to pops/weather through midnight. All and all it`s output seems reasonable showing scattered/numerous showers/storms to gradually weaken and morph into a larger area of rainfall across our area through the evening hours, some of which could be heavy at times along and south of a KSLK-KBTV-KISL line (please see hydro discussion below). After midnight conditions should largely trend dry leaving partly to mostly cloudy skies and seasonable temperatures in the 50s for the overnight hours. Could see some patchy fog in a few spots, but synoptic setup and stronger flow aloft precludes widespread coverage. Another potentially active day then develops on Wednesday as deeper southwesterly flow develops across the area and kicks the stable marine airmass out. Modest instability combined with ample shear aloft should lead to the development of scattered to numerous showers and storms, especially from the Adirondacks east where best forcing and low level convergence will exist. For now have introduced non-severe small hail/gusty winds wording, omitting any reference of severe per marginal SPC SWODY2 output. Temperatures expected to be about 10 degrees warmer than today per 925 mb thermal profiles, mainly upper 60s to lower 70s. By Wednesday night showers/storms exit east by midnight leaving mainly partly cloudy skies overnight. Low temperatures blend of available guidance - mainly from 45 to 55. && .SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/... As of 316 PM EDT Tuesday...Ground Hog Day...the movie...all over again. The steering and driving of our weather continues to be the deep trof with shortwaves rotating around the closed low and timing/position of shortwaves determining the shower threat. Thursday appears to be the day in which the southern extent of the closed low and shortwave pivots across the area. Although deep layered moisture is lacking...persistence, climatology and model data still brings a threat of showers but largely northern and higher terrain and in the morning thus the timing could be diminishing morning showers then more Thu ngt for a relatively drier day. && .LONG TERM /FRIDAY THROUGH TUESDAY/... As of 316 PM EDT Tuesday...Models are fairly consistent through upper low lifts ENE but with another shortwave (there`s always another one) sweeping across the area on Friday night. Thereafter it appears we stay in much broader cyclonic flow with differences between ECMWF/GFS of potentially ANOTHER strong shortwave and closed low rounding the base for Monday. I`m looking for a time that I can leave out POPS but frankly trying to time a long enough period is a guestimate at best. Showers return by Friday morning and become more numerous during the day with possibly enough instability for a few embedded thunderstorms Fri aftn with showers to linger into Sat morning, then drying possibly til Sun aftn until the next shortwave and surface reflection moves into area Sunday night-Mon and still unsettled Tue. Cool, cyclonic flow means temperatures will remain largely AOB seasonable levels through the period. In the real changes from previous forecasts for this time period. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/... Through 00Z Thursday....Showers and isolated thunderstorms continue this evening. MSS most likely site to see some thunder or VCTS. Otherwise, showers expected to exit the area around 06Z. Lots of low level moisture will keep mix of VFR and MVFR conditions throughout the overnight. Expect MPV and SLK to see IFR conditions late this evening through early Wednesday morning. Winds will continue out of the south at 5-15kts, becoming gusty out of the south to southwest during the day Wednesday. VFR conditions return late Wednesday morning with breaks in clouds before more afternoon showers and thunderstorms develop. Outlook... Wednesday Night: VFR. Slight Chance SHRA...Slight Chance TSRA. Thursday: VFR. Breezy. Slight Chance SHRA. Thursday Night: VFR. Chance SHRA. Friday: VFR. Chance SHRA. Friday Night: VFR. Likely SHRA. Saturday: VFR/MVFR. Chance SHRA. Saturday Night: VFR. Slight Chance SHRA. Sunday: VFR. Chance SHRA. && .HYDROLOGY... As of 310 PM EDT Tuesday...Numerous showers and a few thunderstorms will affect the region this evening. The potential still exists for a swath of heavier rainfall to develop across portions of central NY state east-northeast into the southern Adirondacks and central/southern VT. A semi-stationary convergence zone in this area will likely serve as a focus for the activity, which may tend to take on training characteristics. PWATS aren`t overly excessive (1-1.25 inches), but enough confidence given most recent CAM QPF output to support locally heavy rainfall along and south of a KSLK-KBTV- KISL line where scattered totals of 1-2 inches may occur with isolated higher totals. This is in close agreement with latest WPC Day 1 Excessive Rainfall Outlook. While a larger-scale flash flood threat is not expected, 3 hour FFG in this area is running around 2 inches, a bit on the low side. Conditions will be monitored closely as the afternoon/evening progresses. Should training characteristics develop, quick rises on fast- response streams will certainly be possible. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...None. && $$ SYNOPSIS...JMG NEAR TERM...JMG/Lahiff SHORT TERM...SLW LONG TERM...SLW AVIATION...KGM HYDROLOGY...JMG
Area Forecast Discussion
National Weather Service Columbia SC
816 PM EDT Tue May 30 2017 .SYNOPSIS... A diffuse front will remain stalled in the region during the rest of the week. Expect mainly diurnal scattered thunderstorms. && .NEAR TERM /THROUGH WEDNESDAY/... Convection this evening has focused in Georgia. Latest radar indicating weak returns over the CSRA region. Other showers back to the west associated with weak short waves. Air mass across the region will be weakly unstable overnight. Forcing appears weak. Latest high resolution models including HRRR suggest showers in eastern Alabama may move into the CSRA or Piedmont around daybreak. Will keep a slight chance pop overnight increasing slightly around daybreak west. Warm temperatures similar to last night with considerable clouds. && .SHORT TERM /WEDNESDAY NIGHT/... The weak front will remain across the area through Wednesday night. Upper air pattern will still show an east coast trough, with weak high pressure over the area. Models indicate there will still be the possibility of isolated or scattered afternoon showers/storms. 20 to 30 percent pops seem reasonable. Generally went with a model blend of guidance which gives temperatures in the mid to upper 80s through the afternoon, and lows in the middle 60s. && .LONG TERM /THURSDAY THROUGH TUESDAY/... Upper trough remains over the eastern US into Friday before flattening out ahead of another approaching system. At the surface, high pressure will be off in the Western Atlantic through the end of the week, helping to circulate southerly winds and moisture into the region. A cold front is poised to approach the area over the weekend. Can not rule out a slight chance of an afternoon shower/storm on Thursday. Increasing rain chances into the weekend ahead of the next system. Chance pops seem reasonable for now. Temperatures close to normal. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/... VFR conditions expected outside of possible patchy early morning fog and afternoon and evening convection. Most of the shower and thunderstorm activity has remained south and west of the terminals this evening. A slight chance of showers will continue overnight. Cannot rule out patchy MVFR fog in the usual fog prone locations towards sunrise Wednesday morning. However, mid-level clouds over the region will be a limiting factor, so confidence remains too low to include. A frontal boundary in the area on Tuesday will bring another chance for showers and thunderstorms mainly during the afternoon and evening. Confidence in coverage and timing is too low to warrant mention in current TAF issuance. Winds remain generally out of the west through the period. EXTENDED AVIATION OUTLOOK...A cold front will stall over the region through much of the week. The front will help support scattered thunderstorms and possible restrictions each day. && .CAE WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. && $$
Area Forecast Discussion
National Weather Service State College PA
1004 PM EDT Tue May 30 2017 .SYNOPSIS... An upper level trough will remain centered over eastern Canada through the week. With the exception of Thursday, several shortwaves rotating through the trough will bring periods of showers and thunderstorms. && .NEAR TERM /UNTIL 9 AM WEDNESDAY MORNING/... Previously noted short wave touching off isold shra, but coverage is expanding over the NW cos. 30-40 POPs look fine. No risk of thunder there. These should slide steadily NE and may actually exit stage right before sunrise. BFD dewpoint rising and stratus has expanded to cover most of the area east of the Allegheny front. Small holes here and there will only serve to allow fog to form as everyone got wet today and dewpoints are generally just a few degs away now. Prev... Strat-us lurking over Mt Nittany and headed at-us. GOES-R fog difference channel portrays a widespread/expansive and expanding area of stratus over the eastern half of the area. Those that did not lose the stratus will not see clearing and those that did - like State College - soon will have it back. Thanks, east wind. The dewpoints did very briefly touch the 40s in AOO, but it has already popped back into the 60s. Expect the stratus to hang on and fog to form - esp in places that got some decent rain today. We have seen no lingering flooding issues and have allowed all the flood advisories to expire. But, there were a few spots which received >3" of rain. HRRR and RAP do increase the POPs (make some QPF) through the evening hours NW of UNV and in and around BFD and FIG. This seems strange with little instability and dewpoints in the 40s. There must be a subtle short wave in there over OH, but I can`t pick it up on the IR. The only hint is one patch of rain headed quickly for HLG and PIT. This seems on track with the forecast timing of the showers generated by the mdls, so I will hold a small chc in the NW for a few hours around midnight. Have mentioned widespread fog, but the areas which have stratus may not get terribly foggy due to the clouds. On the other hand, it is good to mention as the ridge tops will probably be shrouded in fog as Tussey Mtn is right now. Have kept mins up in the 50s everywhere except the far NW (for now). Even there, the clouds may keep the temps up in the 50s. && .SHORT TERM /9 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/... Next in series of shortwaves is progged to swing through the region Wednesday, accompanied by scattered showers/storms occurring mainly during the afternoon. The eastern half or more of the CWA will start out with a serious handicap on temps - the low stratus and fog. NAM from 18z Tues does keep much of the area dry - only making convection over the NW half. Only a few shra survive into the SE. Will only nudge POPs down in the SE and up a few notches in the NW based on current trends. Despite lack of much CAPE, strong mid level flow and associated 0-6km shear could support organized convection with the threat of damaging wind gusts in a few locations. SPC still have a good portion of the area in MRGL risk - and mainly in the east where the best moisture is. This is at risk if the clouds hang on too long. Well mixed soundings and mean 850mb temps of 8-12C should translate to max temps from the mid 60s over the highest terrain of the Alleghenies, to the upper 70s across the Lower Susq Valley. && .LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/... There is fairly strong model consensus for a mostly sunny/dry Thursday, as surface ridge and associated low PWAT air mass builds across the region. In the longer range, the persistent upper level trough over southeast Canada and the northeast conus will dominant our wx pattern Fri-Mon, producing frequent opportunities for showers and temperatures around to slightly below normal. The best chance for precipitation will be Friday night and Sunday night. Sunday looks like higher QPF amounts but the models have a divergent solution on whether it is a closed low or upper wave. Expect a wet period of weather through the weekend into next week. && .AVIATION /02Z WEDNESDAY THROUGH SUNDAY/... Convection has moved east of all but far southeast/lower Susquehanna Valley airfields /KMDT/KCXY/KLNS...with VFR conds generally in the wake. Few showers moving into the Lower Susq should help stir up the lowered cigs/vsbys in place all day, but probably only temporarily. Models seem to be in agreement with patchy fog/low stratus redeveloping tonight especially over the eastern 1/2 of the airspace with restrictions possible into Wednesday morning. Another round of showers and tstorms looks likely Wednesday afternoon and evening as a cold front pushes east through PA with temporary reductions to MVFR/IFR conds at times. .OUTLOOK... Thu...AM fog/low cigs psbl wrn 1/2. VFR remainder of day. Fri-Sun...Periods of sub-VFR likely with showers and thunderstorms. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Dangelo/Lambert NEAR TERM...Dangelo SHORT TERM...Dangelo/Fitzgerald/Lambert LONG TERM...Fitzgerald/Ceru AVIATION...Lambert/Gartner
Area Forecast Discussion
National Weather Service Cheyenne WY
432 PM MDT Tue May 30 2017 .SHORT TERM...(This evening through Thursday night) Issued at 200 PM MDT Tue May 30 2017 Currently...Water vapor imagery showing upper ridge just moving into western Wyoming this afternoon. Upper low that was over the Great Lakes area yesterday, slowly moving north northeast . Still have northwest flow over the CWFA. Much drier today with PWATs analyzed on area soundings around .38 inches or less. Getting some CU buildups over the north Laramie Range. Most other areas are experiencing pretty flat CU under these dry/stable conditions. Later this afternoon and evening...latest HRRR guidance showing a pretty late start for convective development today. Convection not starting til maybe 23Z at the earliest. Get cells developing over the Laramie Range and then drifting south southeast. It does show some weak thunderstorms over Cheyenne around the 01-02Z timeframe. Do think with loss of surface heating and instability that a lot of this convection will either not materialize or die off quickly. So did keep the Cheyenne area dry. Did add some low PoPs into the south Laramie Range for the 00-02Z timeframe. Upper ridge axis overhead for Wednesday with 700mb temperatures climbing to +8C. Low level winds continue to be forecast to shift to a southeast direction for Wednesday. Do have a very weak shortwave moving through the ridge that could kick off some afternoon convection, particularly over the Laramie Range and areas east. ECMWF and SREF guidance does show some qpf across much of the CWFA tomorrow. Cant rule it out, so have slight chance PoPs going for areas east of the Laramie Range for Wednesday afternoon. Nothing severe expected with surface based CAPE around 500-600 J/KG. Weak upper level steering flow should allow for slow moving storms if they do develop at all, so hazards look to be gusty winds and possibly localized heavy rainfall. Upper ridge axis moves east Wednesday night into Thursday morning with a stronger low pressure system tracking into western Montana and western Wyoming Thursday night. Could see increased coverage of convection mainly out west, closer to the shortwave Thursday afternoon. .LONG TERM...(Friday through Tuesday) Issued at 200 PM MDT Tue May 30 2017 Friday...Westerly flow aloft prevails and with just enough low and mid level moisture present, expect to see isolated afternoon showers and thunderstorms form mainly along and east of Interstate 25. Saturday...As the flow aloft turns northwest, somewhat drier and cooler airmass moves in, producing a more stable airmass and little, if any, chance of showers and thunderstorms. Sunday...Ridging aloft develops with low level southeast winds helping to advect low level moisture northwestward to the foothills of the mountains. This will aid in producing isolated afternoon and evening thunderstorms, mainly along and east of Interstate 25. Monday...Southwest flow aloft strengthens ahead of the Idaho upper low. With diffluence aloft combined with moist upslope in the low levels, expect isolated to scattered afternoon and evening showers and thunderstorms to erupt along and east of Interstate 25, then propagate northeastward across western Nebraska in the evening. Tuesday...Similar pattern to Monday with southwest flow aloft. Perhaps a few degrees cooler due to expansive cloud cover and scattered nature of showers and thunderstorms. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 430 PM MDT Tue May 30 2017 VFR. Isolated showers near Laramie and Cheyenne through 02Z. Wind gusts to 20 knots through 02Z. Wind gusts 20 to 27 knots after 15Z Wednesday. && .FIRE WEATHER... Issued at 200 PM MDT Tue May 30 2017 Fire weather concerns minimal at this time with greenup and recent rain/snow fall. Afternoon humidities could get near critical Wednesday as temperatures warm into the 70s and low 80s. Carbon County looks to be the area where lowest humidities will occur tomorrow. Fortunately, winds are expected to be light and fuels are green, so no fire weather concerns expected. Next chance for widespread wetting rains will be this weekend as another Pacific low pressure system moves through the area. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...None. NE...None. && $$ SHORT TERM...GCC LONG TERM...RUBIN AVIATION...RUBIN FIRE WEATHER...GCC
Area Forecast Discussion
National Weather Service Dodge City KS
600 PM CDT Tue May 30 2017 ...updated aviation... .SHORT TERM...(This evening through Wednesday) Issued at 328 PM CDT Tue May 30 2017 Convective chances exist very late this afternoon beginning in the extreme southwest counties, and spreading slowly eastward through he evening. Moderate instability/CAPE will be present with around 30 knots of bulk shear across western Kansas; an environment which the HRRR drives current ongoing convection across the Sangre de Cristos into by this evening. Given the limited instability and shear, widespread high impact severe weather is not expected; LHP parameter is only indicating around 4 to 5, on the low end of the 1.5 inch hail spectrum, and storm may be too closely clustered as well. Probably more commonly small hail and gusty winds with this event. However the set up by Wednesday may be better suited for severe weather reports (higher CAPE) especially if convection develops earlier in the day across a stationary frontal boundary draped from northwest though central Kansas. A mild overnight with temperatures only falling to the upper 50s, and the models are averaging about 5 degrees warmer than MOS. This will be a jump start to warmer highs as well on Wednesday, as highs climb into the mid and possibly upper 80s south. .LONG TERM...(Wednesday night through Tuesday) Issued at 328 PM CDT Tue May 30 2017 No significant chances to the extended period. Continuing with near climatological weather, with highs in the 80s. Better opportunity for more organized convection will be next week as a western Plains ridge breaks down and low pressure develops across the northern rockies and Central Plains (ECMWF/GFS). && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 600 PM CDT Tue May 30 2017 VFR is expected through TAF pd. Recent mosaic radar trends shows only isolated tsra across NW Kansas. Activity is fairly weak and is not moving very fast. Chance of impacting the terminals is on the low side. Winds will be light/variable tonight to a light southerly wind increasing 10-15 kt tomorrow. && .PRELIMINARY POINT TEMPS/POPS... DDC 57 85 61 85 / 20 40 30 10 GCK 55 86 59 85 / 20 40 30 10 EHA 55 85 58 83 / 20 30 20 10 LBL 57 86 60 84 / 20 30 30 20 HYS 55 83 61 86 / 20 40 30 10 P28 60 87 63 86 / 20 30 20 20 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Russell LONG TERM...Russell AVIATION...Sugden
Please see the 00Z aviation forecast discussion below.

AVIATION... Showers and thunderstorms continue across portions of south central Texas this evening. Radar trends show activity along the I-35 corridor near KSAT and KSSF is decreasing and we will opt to keep -RA in the forecast until 01Z. For the remainder of the evening we should see plenty of mid and high level clouds and this should help keep cigs just above MVFR. The boundary layer continues to cool early Wednesday morning and this along with wet ground should allow some MVFR cigs to develop. MVFR cigs continue through the morning, then lift/scatter back into VFR in the afternoon. With daytime heating, we should see showers around and will carry VCSH after 18Z. Out west at DRT, we have gone with prevailing -RA this evening given plenty of convection over the higher terrain of Mexico. However, we will keep vsbys and cigs VFR. After 08Z, we should start to see a gradual increase in convection and have gone with prevailing -SHRA with cigs just above MVFR. Around 10Z, we should start to see an increase in thunderstorms and have gone with a TEMPO group between 10-14Z. Uncertainty in the forecast after 16Z is high and while we could see additional thunderstorms, we have only gone with VCSH for now. PREV DISCUSSION... /ISSUED 308 PM CDT Tue May 30 2017/ SHORT TERM (Tonight through Wednesday Night)... Ongoing convection will continue to drift east-southeast as semi- persistent MCVs and outflows provide the lift for new convection to develop. There will be an overall reduction in coverage and intensity as diurnal heating ends, and most current activity should die out completely by 03Z. Rainfall will be spotty, but some locations in the Hill Country and San Antonio Metro could receive 1-3 inches of rain. A mid and upper-level low will continue to progress across the Desert Southwest over the next 24 hours. The first shortwave trough rotating around the low is expected to reach the lower Rio Grande by 12Z Wednesday. Mesoscale models, particularly the Texas Tech WRF, HRRR, and experimental HRRR all develop a line of convection or weak MCS over the Sierra Madre, then propagate it eastward ahead of the shortwave trough. This could reach the Rio Grande Plains as early as 09Z, but is more likely closer to 11Z. The low level jet will help maintain this activity through about 15Z...when the climatological diurnal convective lull occurs as the low level jet wanes and before daytime heating ramps up. Additional scattered storms are likely during Wednesday afternoon. LONG TERM (Thursday through Tuesday)... The upper low will continue to progress eastward on Thursday, so another day with fairly high PoPs and the potential for localized heavy rain, but not enough coverage nor amounts to require a flash flood watch. The general flow across North America will be relatively zonal starting on Friday, but will low amplitude ripples, and a bit further south than climatologically normal for this coming weekend and into early next week. Given the generally unchanged moist and slightly unstable airmass in place, this implies scattered showers and thunderstorms, but relatively low 20-30 PoPs, each day. Rainfall will be spotty and generally light, but a few spots could receive a few inches of rain from any given storm. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 70 88 69 85 71 / 20 30 40 70 20 Austin Bergstrom Intl Airport 68 88 69 84 70 / 20 30 40 70 20 New Braunfels Muni Airport 68 86 69 84 70 / 20 30 50 60 20 Burnet Muni Airport 67 84 67 82 68 / 20 40 40 60 20 Del Rio Intl Airport 70 84 69 86 72 / 50 50 60 30 20 Georgetown Muni Airport 67 86 68 84 69 / 20 30 40 60 20 Hondo Muni Airport 69 87 69 86 70 / 40 40 50 50 20 San Marcos Muni Airport 68 87 68 85 70 / 20 30 50 60 20 La Grange - Fayette Regional 69 88 70 86 71 / 20 40 40 70 20 San Antonio Intl Airport 70 87 70 86 71 / 30 30 50 60 20 Stinson Muni Airport 70 87 70 85 71 / 30 30 50 60 20 && .EWX WATCHES/WARNINGS/ADVISORIES... None. && $$ Mesoscale/Aviation...24 Synoptic/Grids...Williams Public Service/Data Collection...YB
Area Forecast Discussion
National Weather Service Hastings NE
649 PM CDT Tue May 30 2017 .SHORT TERM...(This evening through Wednesday) Issued at 232 PM CDT Tue May 30 2017 Primary concern for this time frame include small chances for tstms later this afternoon and then again during the daytime on Wednesday. Looking at the big picture, upper air analysis along with water vapor imagery showing closed low over northern Ontario with troughing over the eastern third/half of the CONUS. A high amplitude ridge prevails over the Rockies with the next upstream low approaching the Pacific NW coast. This puts the central Plains in northwest flow with occasional weak shortwaves rotating through the area. At the surface, weak pressure pattern in place with surface low centered near the upper low over Ontario, with high pressure building into the region from the northwest. Surface dewpoints vary over the CWA, ranging from the mid 30s in the northwest part of the CWA, to the mid 50s in north central KS. First question is what are the chances for tstms in our south later this afternoon? As of 18Z no cumulus development in or close to the CWA. Checking the latest MSAS plots, perhaps some weak convergence going on near the southern CWA but nothing impressive. Models do prog ML CAPE values greater than 500 J/kg in that area. Earlier runs of some of the CAM models this morning had little in the way of convection this afternoon, but last few runs of the HRRR now popping isolated tstms in the KS part of our CWA. Earlier forecast had a slight chance of tstms in this area, and while I don`t plan to up the POPs, probably can`t remove them completely at this point. Precip chances then diminish over night as we lose daytime heating. Will need to introduce POPs again Wed morning starting in the west and then expanding east during the morning hours. Don`t see alot of forcing especially aloft, but the models do forecast a weak low level jet riding over the subtle surface boundary. Time/height section over the middle of the CWA does show decent omega and RH values in the 700-400 mb level from 12-18Z. Believe convection will be spotty across the CWA during the day, so at this point 20 percent coverage should cover it. Instability marginal during the morning hours but becomes more robust during the afternoon with progged CAPE values in excess of 2000 J/kg in the KS part of our CWA. 0-6 km shear could be near 40 kt which is enough to support strong or severe storms. Latest SPC Day 2 outlook has the southwest half of our CWA in a marginal risk, which seems reasonable at this time. Biggest question here is whether the severe threat is centered over our southern CWA or a little south of there. .LONG TERM...(Wednesday night through Tuesday) Issued at 232 PM CDT Tue May 30 2017 Any tstms that develop Wed afternoon should linger into the night before moving off to the east. Thu should be quiet as the upper ridge noted above slides over us. By mid day Friday the ridge axis should be just to our east, with a broad trough moving over the western half of the country. It appears there will be a surface cold front moving through our area sometime Friday afternoon, bringing us our next chance for rain. Models diverge heading into the weekend with the GFS showing more of a progressive flow while the EC builds another ridge into the northern Rockies. However, it also allows a few disturbances to slide under the ridge so either way, continued chances for at least isolated/scattered convection continue into the weekend and the early part of next week. && .AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Wednesday) Issued at 646 PM CDT Tue May 30 2017 VFR conditions are expected. The slight gustiness to the wind will wane after a few hours this evening. && .GID WATCHES/WARNINGS/ADVISORIES... NE...None. KS...None. && $$ SHORT TERM...Ewald LONG TERM...Ewald AVIATION...Heinlein
Area Forecast Discussion
National Weather Service Lincoln IL
907 PM CDT Tue May 30 2017 .UPDATE... Issued at 900 PM CDT Tue May 30 2017 Weak surface trof/cool front continues to edge slowly southeast with isolated showers and thunderstorms located just ahead of the boundary. We expect a slow decrease in activity as we head through the late evening and into the early morning hours with the southeast the last to see the activity move out. A few of the heavier showers produced some strong winds in a few locations with gusts around 50 mph reported in Lane and estimated winds of 45 to 50 mph here in Lincoln early this evening. High pressure is expected to build into our area on Wednesday bringing a quiet weather scene to the area with pleasant afternoon temperatures ranging from the lower 70s far north to the upper 70s along the Interstate 70 corridor. Have already updated the zones to reflect the current thinking with some minor adjustments to the precip wording through the rest of the evening along with some tweaks to the temperatures. && .SHORT TERM...(This evening through Wednesday) ISSUED AT 305 PM CDT Tue May 30 2017 A weak cold front and shortwave will trigger scattered showers and thunderstorms this evening. The front appears to have reached a line from Springfield to Champaign already, but the gradients in dewpoints and winds are not all that noticeable with this weakening front. The showers and storms will be primarily triggered by the shortwave and cold pool aloft that are rotating around the upper low in the western Great Lakes. Cloud-to-cloud lightning flashes have already developed along I-80 just to the north of our counties, so some cloud-to-ground strikes may not be far off as the showers/storms advance southward farther into our forecast area. Have increased the coverage of PoPs/Storms the rest of the afternoon into the evening, which seems reasonable based on the latest updates of the HRRR and RAP models. There are some indications that a few showers/storms may linger south of I-72/74 to Danville after midnight, so have continued isolated chances mainly east of I-57 a couple hours after midnight. Clearing should progress across central IL late tonight, with lows bottoming out in the low 50s toward Galesburg and in the upper 50s toward Lawrenceville. Advancing high pressure on Wednesday should provide a dry day. The colder air aloft will allow for some diurnal cumulus to develop during the afternoon, but high temps should still have enough boost from the late May sun to reach the low 70s north of I-74 and upper 70s south of I-70. .LONG TERM...(Wednesday night through Tuesday) ISSUED AT 305 PM CDT Tue May 30 2017 A warm front advancing north toward Illinois Wed night will produce some increasing clouds late in the night. At some point on Thursday, the models are indicating an MCS will develop in the central Plains and advance eastward toward Illinois. SPC has a Marginal Risk for severe in western Illinois to account for the possibility of that system still producing severe weather this far east. MUCAPEs are projected to reach 1400 J/kg in our western counties, with bulk shear of 30 to 35 kts. Surface moisture will be lacking, so we kept PoPs in the chance and slight chance category on Thursday for now. A secondary storm complex is expected to advance across our northern counties after midnight Thursday night, so PoPs were ramped up to high chance along and north of I-74. Storm chances on Friday and Friday evening look to be on the low side, as the warm front advances north of our counties and we experience a lack of noticeable triggers. The Canadian and GFS show an enhanced area of lift developing after midnight Friday night east of Peoria to Mattoon, mainly due to an apparent southward drift of the warm front toward I-74. High chance PoPs /40-50%/ were included in that area as a result. The surface low is expected to eventually push across northern IL Saturday night, dragging a cold front across the rest of Illinois in the process. High chances of showers and storms will be in the forecast from midnight Friday night through Saturday evening, fueled by MUCAPEs in the 1500-1800 J/Kg range. Bulk shear looks to be weak during that time at 20-30kts. Spotty showers and storms will linger on Sunday into Sunday evening behind the surface low as the upper trough axis and cold pool slowly progress across Illinois. There is relative agreement in the ECMWF/GFS/Canadian that high pressure will settle into Illinois for Monday and Tuesday, increasing the chances of dry weather during that time. However, temps look to be at or below normal under the influence of a cooler Canadian air mass. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 540 PM CDT Tue May 30 2017 A weak cold front will push across the forecast area this evening bringing widely scattered showers and possibly a thunderstorm to central and east central Illinois. We may have to add a tempo group in PIA as the area of showers is closest to that site, while further east and south, coverage at this time looks too limited to carry anything but VCTS for a few hours into this evening. Otherwise, VFR conditions are expected through this forecast period as the weak upper level wave and surface boundary shifts away from our area later tonight with high pressure drifting in for Wednesday. Surface winds ahead of the front will be southwest to west at 12 to 17 kts early this evening with a few gusts around 25 kts, especially in and close to the area of showers. We look for winds to quickly diminish at or just after sunset this evening with a light westerly flow prevailing overnight. Northwest winds are expected on Wednesday at 10 to 15 kts. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Smith SHORT TERM...Shimon LONG TERM...Shimon AVIATION...Smith
Area Forecast Discussion...UPDATED
National Weather Service Jackson MS
915 PM CDT Tue May 30 2017 .UPDATE... Updated for evening discussion. && .DISCUSSION... The afternoon showers and storms have dissipated with the loss of diurnal heating and the CWA is clear of rain at the moment. The hi-res models still show some warm advection showers moving up from south MS and LA overnight and can see some of these already on radar in south LA. Still expect a bit of fog to form in the northern third of the CWA after midnight tonight too. Did not really make any changes to the forecast. Everything looks pretty good so far. /10/ Prior discussion below: This afternoon/tonight through Wednesday: Rain and storms have been ongoing this afternoon across portions along and north of the Highway 82 corridor with some increasing chances slowly as you go towards the I-20 corridor, due to some efficient warming and diurnal heating. Left in some chances of PoPs in the I-20 corridor due to some heating and some of these storms and outflow boundaries helping induce convection near I-20 over the next several hours. HRRR shows this as well over the next few hours so won`t adjust PoPs downward due to this. In this area temperatures have warmed nicely into the lower 80s. The airmass will stay stagnant overnight as the chances of rain wind down over the central and northern half of the area after 00Z. With temperatures falling into the low-mid 60s, especially across the northern half of the area, some patchy to patchy dense fog are possible across the Highway 82 corridor. This is similar to last night into this morning, where we got some decent fog in the Delta. The best chance for patchy dense fog will remain across the Delta. Due to this, added a limited in the HWO/graphics late tonight through mid-morning Wednesday. Expect moisture transport from weak perturbations/shortwaves to move in tonight into south Mississippi, with some PWs approaching the 1.5 to 1.75 inch range, which will help advect back in some showers and storms across south Mississippi. Expect the best chances to come after 07-08Z, with increasing chances towards the I-20 corridor by daybreak and central and northeast Mississippi towards mid morning. These increasing rain chances will continue Wednesday as the boundary lingers around to just north of our area. With a continued feed of moisture transport/convergence, expect scattered showers and storms again tomorrow. With a widespread nature of convection and weak lapse rates/weak flow, expect most storms to remain below strong to severe limits. Due to weak flow, some locally heavy rainfall can`t be ruled out. But these will be scattered enough to preclude mentioning in the HWO. A warm and cloudy day is expected Wednesday in the low 80s in southeast Mississippi where more convection will cause more widespread cloud cover and all. In areas closer to the front, we should warm into the mid 80s, unless some lower clouds/fog hamper heating early in the morning. /DC/ Wednesday night through next Monday: All the models and their ensembles show a generally wet week is in store for the ArkLaMiss as a series of southern stream shortwave troughs dip southward and interact with a persist moisture convergence axis across the Gulf Coast states. Precipitable water values will rise to around 2 inches during the period, especially later in the week when deeper tropical moisture associated with a tropical disturbance near Central America is transported northward through the western Gulf of Mexico. We will get into a mostly diurnal pattern of convection through the rest of the work week, but with greater moisture returning ahead of a more significant shortwave trough this weekend we may see an increase in convective precipitation and at least locally heavy rainfall. We will monitor for the heavy rainfall potential as we get closer in time, but will leave any mention of this out of the graphics/HWO for now. Highs will generally be in the lower to middle 80s with lows in the middle 60s to the lower 70s. /17/EC/ && .AVIATION... 00Z TAF discussion: VFR conditions are occurring this afternoon as most of the ongoing showers and storms are not affecting TAF sites. Some rain is affecting HBG but not enough to limit flight categories. Some fog will be possible for Highway 82 corridor TAF sites later tonight. Another round of rain and storms possible tomorrow, potentially moving in early in the south. /28/ && .PRELIMINARY POINT TEMPS/POPS... Jackson 65 84 68 83 / 14 47 17 55 Meridian 64 83 67 83 / 12 43 15 54 Vicksburg 65 83 68 83 / 12 47 19 60 Hattiesburg 67 82 69 83 / 39 67 18 56 Natchez 66 82 69 82 / 19 56 22 60 Greenville 66 85 68 83 / 10 16 6 52 Greenwood 65 86 67 83 / 12 25 10 52 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...None. LA...None. AR...None. && $$
Area Forecast Discussion
National Weather Service Louisville KY
958 PM EDT Tue May 30 2017 .Forecast Update... Issued at 945 PM EDT Tue May 30 2017 Skies are clear at this time over south-central IN and partly cloudy over south-central KY. Isolated diurnal thunderstorms over south- central KY have dissipated. The question is whether new showers or storms will form overnight as suggested by previous model guidance. Scattered thunderstorms have developed over west-central MO as suggested by models but these are sagging mainly SE. Additional elevated isolated showers and storms over central IL are forecast by the latest HRRR to move east and stay mainly north of our area overnight. The 12z and 18z GFS and NAM suggested isolated to scattered showers and a few storms would develop overnight in our forecast area. The latest HRRR is less enthused about precip in our area, which is supported by the latest observations. But the HRRR does hint that isolated light showers could still occur well after midnight as a weak shortwave rotates eastward to the south of the upper low over the northern Great Lakes. Thus, will leave mention of a few showers overnight, but have trimmed back probabilities. Winds will become light from the S to SW. Current forecasted lows mostly in the upper 50s to lower 60s still looks reasonable. Any isolated showers early Wednesday morning will move quickly eastward out of our area. && .Short Term (Now through Wednesday Night)... Issued at 255 PM EDT Tue May 30 2017 Surface analysis shows a weak surface boundary extending from Indiana to Arkansas. This boundary is moving into an unstable atmosphere (LI around -5 and CAPE 1000-1500) and is sparking widely scattered showers and a few thunderstorms in the heat of the day. This activity should diminish this evening as the sun sets. An upper level disturbance over Minnesota this afternoon will drop southward into the base of an upper trof and help to spark shower redevelopment tonight, especially after midnight. Low temperatures tonight should be around 60. Wednesday the upper trof will gradually push off to the east with scattered shower activity tapering off from west to east. Atmospheric cross-sections suggest that the moisture associated with the showers will decrease quickly behind the precipitation and we`ll probably see a fair amount of partial sunshine by afternoon. So, despite morning rain and clouds will still go for afternoon highs near 80. A compact dome of high pressure over Saskatchewan today will enter the Ohio/Tennessee Valleys Wednesday night and provide quiet weather with lows in the middle and upper 50s. .Long Term (Thursday through Tuesday)... Issued at 308 PM EDT Tue May 30 2017 An upper ridge over the Plains early in the long term will try to move east but instead will get squashed by an upper low sinking southeast out of Canada and across the Great Lakes over the weekend and into early next week. A slug of deeper moisture is expected to advect in from the mid- Missouri Valley to the Ohio Valley Thursday afternoon and night. A very subtle wave crossing southern Illinois may spark some thunderstorms in the afternoon and evening. High pressure will still be in the vicinity at the surface and the operational GFS is likely overdone with its QPF with this feature, though, so will lean toward the drier ECMWF/GEM and keep PoPs low. That surface high will continue to push to the ESE and eventually absorb into high pressure over the Atlantic. This will put southern Indiana and central Kentucky on the back side of the large swath of high pressure and in an area of southerly 1000-700mb flow bringing Gulf moisture northward...especially Friday through Sunday morning. To trigger convection, a complex storm system will proceed from the upper Plains through the Great Lakes and OV on its way to the Northeast. Soundings, especially in southern Kentucky Saturday evening through Sunday morning, become very wet. This is reflected by precipitable water amounts approaching 1.8 inches. Deep flow looks to be on the weak side. So, heavy rainers will be a possibility. WPC has indicated a swath of high QPF along the KY/TN border, but it should be noted that there are still large differences among the models. High pressure nosing in from Canada should then dry us out for the beginning of the new work week. && .Aviation (00z TAF Update)... Issued at 740 PM EDT Tue May 30 2017 Skies are mostly clear over southern IN and partly cloudy over southern KY at this time, with diurnal isolated convection downstate dying off. Area will be precip free next few hours. Then a weak disturbance to our west could again initiate isolated to scattered showers (perhaps a thunderstorm) later tonight as it tracks across KY. Have included VCSH in all 3 TAFs after 06z for a few hours. However, prevailing conditions should remain VFR, unless a quick downpour briefly lowers vsbys over the terminal. Prevailing winds overnight will become light from the south. On Wednesday, any sct showers overnight will exit east in the morning with surface winds becoming SW and then W around 10-12 kts in the afternoon with VFR conditions. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...None. KY...None. && $$ Update.........TWF Short Term.....13 Long Term......13 Aviation.......TWF
Area Forecast Discussion
National Weather Service Mount Holly NJ
1204 AM EDT Wed May 31 2017 .SYNOPSIS... A stationary front will remain to the south of the region through Wednesday. A surface trough will weaken as it approaches the area tonight. A cold front will move through the Northeast Wednesday and Wednesday night. High pressure briefly builds into the East to close the week. A cold front will sag southward from southern Canada this weekend. A surface low will move into the Northeast early next week. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... Widespread fog and drizzle across the region through the overnight. Some spots have dropped to under a mile, and it is possible for patchy dense fog, but will hold off on a Dense Fog Advisory. Area of showers and thunderstorms south and east of Washington D.C. and tracking to the east. Could have some of those showers and storms entering southern portions of northeast Maryland and southern portions of Delaware through the early morning hours. Latest HRRR has it passing through there from 05-08Z. Very little, if any SBCAPE, but MUCAPE ranges from 750-1000 J/kg, so there should be enough elevated instability to keep storms alive. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/... It appears the the low level moisture will finally begin to decrease over the area, allowing at least some sunshine across the forecast area Wednesday. An approaching front will cause winds to become S or SWrly during the morning. This will help mix out some of the trapped clouds over the area. Temperatures will respond by climbing into the low/mid 70s across the north and close to 80 over Delmarva and metro Philadelphia. We will continue to carry the chc for showers and tstms for the afternoon. The favored areas will be N/W, however. && .LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/... Main concern in the long term is the potential for a prolonged period of occasional chances for showers and storms Friday through early next week. Model discussion: The operational model suite continues to struggle with the evolution of a high-amplitude ridge in central Canada through the period, with omega blocking in Canada and the presence of weak high-over-low blocking in the central U.S., at least through the weekend. Though the details of the planetary- scale features have improved somewhat compared to this time yesterday, the smaller-scale perturbations within both the large-scale trough in eastern Canada and the low-amplitude flow over the conterminous United States continue to be large sources of model variability from run to run (and from model to model). Thus, the forecast remains very low confidence Friday onward, with potential for considerable changes to portions of the forecast as the setup/event(s) approach(es). Many of the model discrepancies in yesterday`s discussion remain to some degree, including the westward bias of the CMC with regard to the placement of the first upper-level low in eastern Canada that will eject eastward early this weekend. The GFS becomes a somewhat deep/slow outlier as the trough pivots eastward into New England on Saturday, though closer to consensus than yesterday. Considerable spatial variability remains with the reloading vort max late this weekend, with subtle but important differences in timing/phasing with the southern-stream vort max progressing eastward through the central U.S. Nevertheless, the operational models are beginning to stabilize on their solutions, with the 12Z ECMWF showing a strong surface low progressing into the Great Lakes region and stalling late this weekend into early next week before pivoting southeastward through the Northeast. The 12Z CMC has, for several days, suggested a more zonal track of the low through the Midwest/Ohio Valley into adjacent New York and the northern Mid-Atlantic during this same period. The GFS remains the most variable of the three, but has consistently produced a more southern track of the surface low (which is internally consistent with its somewhat deeper upper-level trough). Finally, the 12Z CMC continues to show a southern-stream low developing in the Gulf of Mexico moving northeastward through the Mid-Atlantic (or vicinity) early next week, though substantial variation exists on track and timing. Unfortunately, larger discrepancies remain with smaller-scale lift and associated precipitation, which will largely depend on the aforementioned vorticity maxima and their interactions through this period. Forecast skill with these details is simply too low at this time range to provide specifics. The forecast details below provide information on the details that appear to be emerging from the model chaos, but as these trends are just developing and subject to large errors owing to the low- predictability pattern, there remains a long way to go in sifting through the "close-to-reality" versus the computational garbage. Forecast basis was a 30/25/25/20 blend of the ECMWF, NAM, GFS, and CMC (respectively) through Friday followed by a 30/25/25/20 blend of the ECMWF, GFS, CMC, and WPC guidance thereafter. Modifications were made to include statistical guidance for temperatures (and to lesser degrees, PoPs and QPF) to increase collaborative agreement with surrounding offices. Forecast details: Wednesday night: Remnant convection from a cold front moving through the area is expected to continue but weaken rapidly with loss of daytime heating. Primary chances appear to be in the southern CWA, though slight chances remain farther north based on more aggressive look to longer-range higher-resolution guidance to this point (e.g., the RGEM). Kept lows close to a MAV/MET consensus here, with improving skies overnight. Thursday and Thursday night: Nice day. With transient shortwave ridging upstream of the departing vort max and attendant surface ridge moving through the Eastern Seaboard, a seasonal day with mostly sunny skies is expected. There could be some wind gusts 20 to 25 mph or so, as deep mixing is expected upstream of the cold front with 850-mb flow around 30 kts. Temperatures on Thursday night may be a little cooler than Wednesday night with calmer winds and clearer skies. Friday through Saturday: A vort max from central Canada digs southeastward to the U.S./Canada border near/east of the Great Lakes during the period. A strong, cyclonically-curved 250-mb jet streak intensifies as it rounds the base of the longwave trough. An attendant baroclinic zone will develop from the Ohio Valley eastward to the Atlantic coast, with only slow movement of this front/temperature gradient southward given upper-level flow nearly parallel to the surface boundary. Strength of the vorticity maximum and substantial warm advection downstream will provide sustained large-scale lift in much of the eastern U.S. during this period. However, with antecedent drying from the cold front moving through during the short-term period, there is some question regarding the degree of moistening/destabilization for precipitation coverage during this period, with the GFS notably dry (mostly from poor timing of the deepest lift -- i.e., this occurs Friday night, when instability will be naturally more limited) and the CMC too far south with the moisture pooling (which may be suspect, since it is on the fast side of the guidance envelope with frontal passage). PoPs were capped at chance during this period given these discrepancies. Saturday night: More disagreement, as the GFS moves another vort max through the region, with considerable precipitation breaking out across the baroclinic zone (now positioned generally south of the CWA). The ECMWF suggests this to some degree as well, but pushes the front much farther to the south. The CMC does not show much hint of this at all, and places the front well to the south. The CMC looks unreasonable here, as the upper-level flow does not really justify such a southward push. Thus, think slight chance to chance PoPs are a reasonable forecast for now, though this may end up being a dry period. Chances are primarily for showers during this period given the reduced instability on the north side of the boundary. Sunday and Monday: A strong surface low approaches the region from the west. GFS/ECMWF solutions look wet, but there is disagreement on the nature of the precipitation. The farther south GFS low track would suggest a heavy rain event (with little thunder), but the ECMWF and drier CMC suggest a somewhat more convective look to the precipitation, particularly in the southern CWA. Hard to say at this time frame, as competing factors are in play here (including models` general inability to simulate cold air damming versus models` general tendency to push cold fronts too fast in patterns like this). For now, generally chance PoPs in this time frame with slight chance of thunder. Potential for heavy rain in this period, but details too unclear to include mention at this time. Pattern recognition suggests this a time window worth watching closely. Tuesday: Longwave trough persists in eastern U.S./Canada. Cool and showery look to the simulations on the upstream side of the low. Kept slight chance PoPs during this time. && .AVIATION /04Z WEDNESDAY THROUGH SUNDAY/... The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas. Widespread IFR/LIFR CIGs/VSBYs during the overnight with LGT/VRB to calm winds. Conditions improve throughout Wednesday morning, becoming VFR by Wednesday afternoon. Scattered SHRA/TSRA in the afternoon. OUTLOOK... Wednesday night: Scattered showers/storms in the evening, then clearing skies with west/northwest winds at or below 10 kts. Confidence average. Thursday and Thursday night: VFR. Winds west or northwest 5 to 15 kts with gusts to 20 kts or so during the day and below 10 kts at night. Confidence well above average. Friday through Saturday night: Gradually deteriorating conditions, with locally MVFR/IFR conditions in proximity to showers and storms Friday night and Saturday. Southwest winds 5 to 15 kts. Winds may become north/northeast on Saturday or Saturday night, with longer-term MVFR/IFR conditions possible thereafter. Confidence well below average. Sunday: Potential for MVFR/IFR with chances of showers/storms. Winds generally east or southeast 5 to 15 kts. Confidence below average. && .MARINE... Offshore buoy data continues to be missing. Sub-SCA conditions on the waters with LGT/VRB winds and 3-4 ft seas on the ocean. Fog/drizzle will reduce VSBY to 1-3 NM. There is the potential for VSBY less than 1 NM, and if VSBY continues to deteriorate, will issue a Marine Dense Fog Advy. OUTLOOK... Wednesday night through Thursday night: Sub-advisory conditions expected. Chance of showers/storms Wednesday evening. Friday and Friday night: Marginal advisory conditions possible with gusts around 25 kts and seas building to around 4 to 5 feet. Low confidence at this time. Saturday through Sunday: Sub-advisory conditions expected. Chances of showers and storms through much of the period. RIP CURRENTS... The potential for the development of dangerous rip currents is moderate today, with a low risk currently anticipated for Wednesday. && .TIDES/COASTAL FLOODING... As astronomical tides continue to fall, the threat for coastal flooding will be reduced, even through the onshore flow continues. Therefore, no coastal flood advisory was issued. && .CLIMATE... ACY now 7.5" for the month ranked #2 behind the 8.8 in 1948. POR 1874 PHL now 6.33 for the month ranked #11. record 9.46 -1894. POR 1872. #10 is last years 6.65 Since the 20th of May including today its rained a trace or more PHL 9 of 11 days ILG 9 of 11 days including current 9 consecutive ABE 10 of 11 days including current 7 consecutive TTN 10 of 11 days including current 7 consecutive. ACY 9 of 11 days including current 9 consecutive MPO 9 of 11 days including current 6 consecutive RDG 9 of 11 days GED 9 of 11 days The month will generally average below normal to varying values of generally 1 degree or less, except MPO around 2.5 degrees. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...None. NJ...None. DE...None. MD...None. MARINE...None. && $$ Synopsis...CMS Near Term...MPS Short Term...O`Hara Long Term...CMS Aviation...CMS/Kruzdlo/MPS/O`Hara Marine...CMS/Kruzdlo/MPS/O`Hara Tides/Coastal Flooding... Climate...