Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 05/17/19

Area Forecast Discussion
National Weather Service State College PA
1131 PM EDT Thu May 16 2019 .SYNOPSIS... A weak front will drop through the area Friday. This front will remain close to the region keeping the mention of a shower in the forecast through the weekend into early next week. Temperatures will continue to moderate through the period. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... New convection is firing over southern Michigan/NRN Indiana and looks aimed at SWRN PA. The HRRR shows this entering my western zones between about around sunrise and mainly dissipating as it passes through my SWRN zones. It does show scattered showers over much of the remainder of the forecast area, but the overall coverage suggests being less pessimistic about the rain chances late tonight and especially during the day Friday. The increasing clouds and 5-10 mph SW breeze will lead to overnight min temps generally in the low-mid 50s. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/... GEFS indicates Highest PWAT air (30-35MM over Western and Central PA early Friday) will sag south to the Southern Tier counties of PA by 18Z Friday, with negative LLVL Theta-E advection across the Central and North. PWAT values by late Friday afternoon will dip to under 20 MM along the PA/NY border. Will layer pops for Friday afternoon from only 20-30 percent across the northern tier of PA where ML capes will be nil, to near 60 Percent across the Laurels, where CAPE will be on the order of 1500-2000 J/KG. Granted, there will likely be a sharper gradient, but there is still some uncertainty near and just south of the I-80 corridor whether a few stray showers could wet the ground or we`ll see dry conditions after the brief bout of dissipating morning showers/isolated TSRA. Thunder chances are probably highest late tonight (west) and then again in the aftn, but mainly in the Scent and SW. SPC does have much of the southern tier counties in our CWA within their MRGL risk for svr storms on Friday (DY2). Temps should rebound to the m60s in the N, but get close to 80F along the MD border. && .LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/... *Trending warmer and more humid Saturday-Monday *Dry breaks but still can`t rule out a couple of showers or t-storm through Monday *Tuesday looks cooler/less humid with increasing chance for rain into midweek Rising heights and building upper level ridging will spell a warmer and more humid sensible wx trend through the weekend into early next week. While there will be plenty of dry breaks, we still cannot rule out a few spotty showers or isolated t-storm during this time. Expect sparse coverage with limited rainfall. We are fairly confident that Tuesday will be dry and and bit cooler/less humid. Model and ensemble guidance shows an increase in rain risk heading into the middle of next week. && .AVIATION /04Z FRIDAY THROUGH TUESDAY/... Clouds will gradually thicken and lower overnight. Ceilings should drop to MVFR (possibly IFR) over the western highlands /KJST and KBFD/ by daybreak, with brief vsby reductions possible in showers. Included LLWS at all airfields overnight into Friday morning, as a 30-45 kt WSW low-level jet is expected to push across central PA. A weakening area of shra/tsra could brush SW PA towards daybreak on Friday. A few additional shra/tsra are expected to develop by afternoon, as a weak cold front crosses the area. .Outlook... Fri...AM low cigs and shra possible NW mtns. Scattered aftn shra/tsra impacts possible. Sat...Isolated aftn shra/tsra possible western highlands. Sun...Scattered aftn shra/tsra possible area-wide. Mon...AM low cigs possible NW mtns. Scattered aftn tsra impacts possible eastern PA. Tue...mainly VFR. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...La Corte NEAR TERM...La Corte SHORT TERM...Lambert LONG TERM...Steinbugl AVIATION...Evanego
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1158 PM EDT Thu May 16 2019 .AVIATION... A cold front will settle southward across the area overnight. This will allow drier and more stable conditions to develop under post- frontal northerly winds. There is the potential for a brief period of MVFR to low VFR stratus to emerge during the early-mid morning period immediately behind the front. Any lower ceiling with lift with daytime heating by midday. The frontal boundary is forecast to stall across the Ohio valley on Friday, maintaining a dry north- northeast flow through the day. This will ensure VFR conditions hold into the evening period. .DTW THRESHOLD PROBABILITIES... * Low for ceiling 5000 ft or less through Friday. && .PREV DISCUSSION... Issued at 848 PM EDT Thu May 16 2019 UPDATE... Expanding corridor of convection emerging across northern Indiana late this evening, driven by rapidly diminishing mid level stability as a plume of higher 850-700 mb moisture works across a weakly unstable boundary layer. Downstream profile across southeast Michigan not nearly as favorable, noting the lack of surface based instability within the existing low to mid 50s dewpoint airmass. Little evidence to suggest this will change going forward, leaving simply a narrow window for elevated convection to develop generally along/south of the I-96 corridor as mid level moisture briefly increases over the next 3-5 hours. The underlying magnitude of the deep layer shear could allow for greater organization, but lack of instability throughout the column will keep this potential to a minimum. Brief heavy rainfall and small hail the most likely outcome with any stronger cores early tonight. PREV DISCUSSION... Issued at 355 PM EDT Thu May 16 2019 DISCUSSION... Continue to monitor convective trends for the potential of Severe Weather across Southeast Michigan this evening. Per RAP based mesoanalysis, instability recovery has been non-existent to this point with edge of MUCAPE/SBCAPE back across the IL and IN stateline. Orphaned off MCV feature with high based glaciated light shower/virga activity is currently working eastward through portions of Lower Michigan this afternoon. This activity is on the lead edge of the 700-600mb warm advection. It is going to take awhile yet to moisten the low levels and lower LCL heights as dewpoints are still in the low to middle 50s. Despite convective debris cloud for a good chunk of today, still expecting air mass change with high end warm advection event this evening as longer wavelength theta e ridge propagates through the central Great Lakes region. Long May daytime and a break out of some sunshine late this afternoon still supports some lower tropospheric instability recovery. No changes to earlier thinking. A potential exists for thunderstorm activity this evening south of a line from Owosso to Mount Clemens. Slight Risk for severe weather/damaging wind gusts remains conditional to the development of a forward propagating cold pool. Greatest potential for severe weather appears set to the approximate 3-6 Z time window generally south of the I 94 corridor. If the cold pool does not develop, a marginal risk for large hail will exist for Southeast Michigan. Limiting factors will be no EML/steep midlevel lapse rates and relatively high stability in the 2.5-5.0 kft agl layer. Surface ridge with help from the lake aggregate will expand southward into Lower Michigan 06-18Z Friday. Composite frontal boundary/cold front will sag south of the cwa. Forecast soundings support active subsidence for much of Friday with strong midlevel inversion in the 4.0 to 10.0 kft agl layer. Proximity of the composite boundary supports various cloud over southern half of the cwa. Pleasant temperatures with highs in the middle to upper 60s. Longwave ridge amplification will for well defined warm front northward through Southeast Michigan Friday night. Strong forcing for ascent is progged along the elevated frontal zone centered between 800-700mb. Current forecasts read likely to categorical PoPs between 06-12Z Friday. Forecast soundings support high static stability in the lowest 7.0 kft agl which limits potential for strong thunderstorm activity. Amplifying warm sector will bring warmth to Southeast Michigan on Saturday. Difficult forecast from a gridded perspective with differential heating boundary wreaking havoc on the guidance. Gut feeling is that the current forecast is too cold, particularly for the central and northern cwa. Highs for many areas will likely reach upper 70s. A strong surface low over the central Plains will continue to push into the Great Lakes region early Sunday. Southern lower MI will already be in the warm sector as the warm front will have pushed north of the region Sunday morning. By Sunday afternoon, showers and thunderstorms will move into SE MI from the west as the upper level trough begins to move over the area. This precip will stay over the area through Sunday night as the cold front begins to push across SE MI. The front will be east of the area by Monday afternoon causing a sizable drop in temperatures for both Monday and Tuesday. A ridge of high pressure follows the low allowing for drier weather Monday through Tuesday night. A shortwave develops over the central plains and begins to move into the Great Lakes region late Tuesday night. The associated warm front pushes into SE MI Wednesday morning bringing some rain chances for the daytime Wednesday. The system moves across Lake Superior into Ontario by Wednesday night with drier conditions prevailing over lower MI. Ridge of high pressure moves into the area Thursday. MARINE... Episodic thunderstorms during the upcoming week as two cyclones lift through the Great Lakes region. The first chance will be tonight, mainly over Lakes Saint Clair and Erie where a low end severe wind threat will exist. General thunder Fri night will then be followed by a more organized severe weather threat ahead of a cold front on Sunday. Wind generally be moderate to fresh and tending to veer from one day to the next. HYDROLOGY... Thunderstorms are forecast to develop and sweep through the southern half of the area after about 8pm this evening. Although coverage and intensity of any storms remains uncertain, basin average QPF around one half to three quarters of an inch will be possible over the southern two tiers of counties with the probability for higher rainfall totals increasing with south and westward extent. Showers and thunderstorms will be common during the next week, returning again Friday night and Sunday as the parent low lifts through the area. Another low will follow a similar track during the middle of next week. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. Lake Huron...NONE. Lake St Clair...NONE. Michigan waters of Lake Erie...NONE. && $$ AVIATION.....MR UPDATE.......MR DISCUSSION...CB/KDK MARINE.......JVC HYDROLOGY....JVC You can obtain your latest National Weather Service forecasts online at
Area Forecast Discussion
National Weather Service Hastings NE
321 PM CDT Thu May 16 2019 .SHORT TERM...(This evening through Friday) Issued at 309 PM CDT Thu May 16 2019 Short term concerns are centered around thunderstorms this evening and again tomorrow afternoon and evening. This evening, a stalled cold front will be the main focus for thunderstorms. Currently, this front stretches from far southwest Nebraska up through LXN and ODX and into northeast Nebraska. Given relatively weak forcing aloft, I expect coverage to remain pretty isolated. In addition, low-level moisture and deep-layer shear are both a bit lackluster (especially compared to tomorrow), so I don`t expect any significant severe weather tonight. That being said, RAP mesoanalysis shows around 1000J/kg of MLCAPE and 20-30kts of effective bulk shear...which would be marginally supportive of severe storms. Expect thunderstorms to continue to move to the northeast through the night, exiting the area by Friday morning. Stronger forcing arrives on Friday as the main trough. As the front pushes back north, we will see good instability develop over Nebraska and Kansas...on the order of 3000-4000J/kg of MLCAPE. Shear will also increase substantially as the upper trough moves in, with 40-50kts likely over portions of the area. All that being said, the highest coverage of thunderstorms will likely end up being west and north of the local area. The surface low isn`t forecast to move into far SW nebraska until almost 03Z...which isn`t great timing for severe weather in the local area. Nevertheless, any storms that manage to develop in this environment could become severe with very large hail, and damaging hail and possibly an isolated tornado or two. But again, I want to reiterate that we are expecting the majority of the severe weather to be north and west of the local area...primarily over the Nebraska Sandhills. .LONG TERM...(Friday night through Thursday) Issued at 309 PM CDT Thu May 16 2019 By Saturday morning, cold front is forecast to have pushed through the area, so severe weather should focus well to our southeast. Even so, we will likely have scattered showers and weak thunderstorms as the upper trough axis moves through. Sunday should be mostly dry, but will be significantly cooler with highs only in the upper 50s and 60s across the area. That is almost 30 degrees colder than the high temperatures that we`re seeing today. The cool pattern continues Sunday night into Monday as the next trough moves into the area. This brings widespread chances for rain and thunderstorms Monday through Tuesday. Its still early, but WPC`s 4-5 day QPF shows 1-3" of rain across this area during this timeframe...certainly not good news for farmers that are still trying to get fields planted. Beyond Tuesday, the area will remain in broad southwesterly flow aloft, which will lead to a gradual warming trend into the middle and latter half of the week. Wednesday and Thursday should remain mostly dry, but the model consensus still keeps some slight chances for rain and thunderstorms in the area ahead of yet another western trough that will be approaching the area. && .AVIATION...(For the 18Z KGRI/KEAR TAFS through 18Z Friday) Issued at 1225 PM CDT Thu May 16 2019 Isolated thunderstorms are expected in the vicinity of the terminals this evening. Then late tonight, we will see LLWS develop as the low-level jet increases. On Friday, winds will remain southerly and increase as the warm front lifts north. && .GID WATCHES/WARNINGS/ADVISORIES... NE...None. KS...None. && $$ SHORT TERM...Mangels LONG TERM...Mangels AVIATION...Mangels
Area Forecast Discussion
National Weather Service Grand Rapids MI
743 PM EDT Thu May 16 2019 LATEST UPDATE... Aviation .SYNOPSIS... Issued at 326 PM EDT Thu May 16 2019 - Several opportunities for showers and storms through next week. - Strong/severe storms possible Sunday and to a lesser extent this evening. - High temperatures inching closer to normal. && .DISCUSSION...(This evening through next Thursday) Issued at 326 PM EDT Thu May 16 2019 Satellite and regional radar show a MCS moving southeast across NW Indiana. What was a more broad convective complex this morning has morphed into a bow echo this afternoon and it moving away from Michigan. The cwa has been under the cloud shield for much of the day and this has limited instability over the SW Michigan. It`s possible as the clouds thin late this afternoon, instability may increase. A few storms have developed over far southeast Wisconsin. Latest HRRR shows some convection firing near GRR around 01z and other short range models have shown this too; we`ll keep high POPS in the grids this evening for our southern cwa. Today`s convection was firing along a cold front dropping south and this frontal boundary will be a player in our weather through Friday. The boundary will drop south into northern IN tonight, but begin to move north tomorrow. Showers and storms are possible along the northward moving frontal boundary from mid afternoon on. The GFS shows a weak wave moving east across the lake toward 00z and that may enhance any storms that develop. There is some instability and shear so a few strong storms are possible. We`ll be south of the warm front Saturday and so most of the showers/storms will be north of the cwa. Sunday may be a different story. A deepening low will move northeast across Wisconsin and push a cold front east toward lower Lake Michigan. Should be quite a bit of lift with the front along with instability and shear. LLJ increases to 50+ knots too so severe storms looks possible from noon on. After the Sunday system moves east, the next low that will affect us will arrive mid week and give us a chance at showers/storms. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 743 PM EDT Thu May 16 2019 Showers and thunderstorms will remain scattered this evening with the highest chances across far southern Lower Michigan. Some brief IFR is possible with heavier storms. Areas of IFR are also possible across southern Lower Michigan after midnight as low stratus with ceilings blo 1000 feet. && .MARINE... Issued at 326 PM EDT Thu May 16 2019 Northwest winds 10 to 20 knots will become northeast overnight. Waves through Friday are expected aob 3 feet. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. LM...None. && $$ SYNOPSIS...04 DISCUSSION...04 AVIATION...Ostuno MARINE...04
Area Forecast Discussion...UPDATED
National Weather Service Gray ME
940 PM EDT Thu May 16 2019 .SYNOPSIS... Low pressure over the Great Lakes this evening will move through the region on Friday bringing another round of showers and cool temperatures to the area. High pressure will arrive on Saturday with drier conditions and warmer temperatures. Showers are again possible on Sunday as a warm front lifts into the region. Significantly warmer will likely arrive behind this front for the day Monday before a cold front brings temperatures back to around normal for this time of year for the middle of next week. && .NEAR TERM /THROUGH FRIDAY/... 930 PM Update... Satellite imagery shows drier air now moving through eastern New Hampshire and western/central Maine. Addition cloud cover is moving in aloft from Canada. In the meantime temperatures will continue to fall at a good clip with dew points in the upper 30s and lower 40s across the region. Only a few tweaks to the forecast a this point with warmer air aloft arriving overnight ahead of the next system. 630 PM Update... Weak ridging is building in tonight allowing for a brief decrease in rain and cloud cover/opacity overnight. Made a few minor changes to the forecast for current temperature and dew point trends. Precipitation timing towards morning looks on target and close to most recent NAM Nest and HRRR runs. Previous discussion... High Impact Weather Potential: Minimal. Pattern: After a bright air aloft associated with departing shortwave trough has resulted in another cool day withs some light showers across the region. Upstream...a narrow short wave ridge axis in the mid levels of the atmosphere is building towards the region from the west. This...and it/s associated reflection at the surface will move overhead tonight...but progressive northwesterly flow aloft will usher in another shortwave which will be west of the region but beginning to impact the area by daybreak Friday. Thus...forecast concerns are centered around precipitation chances as this wave...and associated fast-moving surface low pressure system approach from the west. Through this evening: Sprinkles/light showers continue along a band from Littleton, NH south and east through the Midcoast /given cyclonic flow and impressive lapse rates in the 0-10kft layer/...with additional activity arching southwest along the coast of ME and NH. This will continue through mid evening before cooling boundary layer temperatures will stabilize things and bring this activity to an end. Temperatures will fall back into the 50s south of the mountains by 8pm...with values reaching the upper 40s by this time for many locations from the mountains north. Tonight: Low pressure centered just north of Sault Ste. Marie this evening will move east to a position just north of Lake Ontario by daybreak Friday...with a surface warm front draped south and east of this feature to the south and west of New England. Narrow ribbon of isentropic ascent will allow for top- down saturation through the night with increasing clouds and slowly strengthening southerly gradient. SREF/HREF probabilities along with recent runs of the HRRR suggest shower activity will begin to encroach on our western zones in the pre-dawn hours and will increase PoPs from west to east as we reach 7am. Guidance moisture profiles and HRRR simulated satellite imagery suggests that opaque cloud cover will not arrive until well after midnight which should allow temperatures to fall pretty rapidly...with lows in the mountains likely falling into the 30s...with lower 40s across the remainder of southwestern ME and some mid 40s over southern NH. && .SHORT TERM /FRIDAY NIGHT/... High Impact Weather Potential: Minimal. Pattern: Slowly sharpening shortwave trough embedded in northwest flow aloft will cross the region on Friday before drier air arrives Friday night as shortwave and associated surface low passes east of the region. Primary forecast concerns are centered around rainfall timing/amounts on Friday. Friday: Occluded low pressure system moves east through the day Friday along the international border to a location just north of western Maine by Friday evening...with a triple point moving through central VT and southern NH to near KPSM by Friday evening. Veered LLJ suggests pretty weak forcing for ascent at the leading edge of 1-1.25" PWAT moisture plume that will reach southern NH by early Friday afternoon before being pushed to the south and east. The rain appears to be pretty much a daytime event...with showers likely coming to a end even over western Maine towards evening. Based on the position of the triple point...there is the potential for some weak instability to reach into southwestern NH...but model soundings are not conducive to thunder as dry air aloft arrives rapidly by the middle of the afternoon. As for temperatures...T8s reach about 6C over SW NH during the afternoon /fully mixed would yield near 70F/ but with cloud cover and precipitation...expect that we will not quite fully reach these values...with middle 60s likely over southern NH...with lower highs to the north and east of this which will see showers/clouds longer and will be north of the triple point. As for precipitation amounts...most locations will likely see only 0.1-0.2" given the aforementioned weak forcing...however some enhancement in the terrain is likely with 0.25-0.4" possible here. Certainly not enough to cause any hydro issues. Friday Night: Low pressure pulls off the Maine coast Friday evening and strengthens as it moves to a position over Nova Scotia by daybreak Saturday. A pretty impressive surge aloft of dry/Polar air will arrive behind this departing low with PWATs rapidly falling below 0.5" /-1 to -2 sigma/ with a modest gradient and cold air advection allowing for northwesterly winds to continue through the night. The winds...and lack of robust dry advection in the llevels will keep lows from dropping all that far with lows ranging from around 40 in the mountains to the upper 40s over southern NH and along the coast of SW Maine. && .LONG TERM /SATURDAY THROUGH THURSDAY/... A battle between spring and summer looks to be in the cards for much of ME and NH Sunday and Monday as a warm front wavers around the region. Run to run consistency hasn`t been very good over the last couple of days and this may result in fairly large temperature bust potential Sunday and possibly again on Monday. First thing first, Saturday looks to be a nice day as a weak sliver of high pressure builds overnight. This should allow for at least partial sunshine with high temperatures slightly below normal. A warm front approaches Saturday night while sharpening up quite a bit by Sunday morning. Forcing for ascent will increase Sunday morning allow for on and off showers much of the day. Even a few thunderstorms will be possible as instability increases aloft. the big question is where does the SFC warm front end up on Sunday. Members of the 12z model suite are offering different positions, but the main theme is that a sharp warm front should be draped in W-E fashion somewhere in the forecast area or nearby. Large temperature errors will be possible. Blended the available temperature data at this time due to the uncertainty. However, it could get quite warm in the south. The same applies for Monday with the SFC warm front slowly moving its way northward. Again, warm frontal positions are hard to pin down this time of year as they tend to struggle. However, there is general agreement that the forecast area will get into the warm/moist sector on Monday. Have therefore raised high temperatures. May very well see the warmest day of the season thus far with highs reaching 80 in many areas. However, it wouldn`t take much of a southwestward push from the cooler maritime air mass to the northeast to wipe out that potential for some. With a cold front moving in from the west during the afternoon, have gone with a chance of showers and thunderstorms. Various models show warm sector SBCAPE values getting well above 1000 J/KG with SFC dewpoints well into the 60s. So something to watch there in terms of thunder potential. Cooler, drier air is expected to return for Tuesday and Wednesday in the wake of the cold front. Thereafter, another round of WAA-aided precipitation is possible midweek. && .AVIATION /02Z FRIDAY THROUGH TUESDAY/... Short Term... Summary: Low pressure will approach the region from the Great Lakes tonight...passing overhead on Friday before moving into the Canadian maritimes Friday night. Restrictions: VFR through at least daybreak Friday. Arriving frontal system will bring deterioration on Friday in SHRAs with IFR restrictions likely for our Maine terminals /and potentially PSM/ with MVFR likely in NH. Conditions will rapidly improve to VFR Friday night. Winds: Northwesterly winds 5-10kts with coastal seabreeze expected through this evening with winds going calm/light- variable overnight. Southeasterly winds 5-10kts develop on Friday...becoming southwest over southern NH during the afternoon before turning northwest around 10kts Friday night. LLWS: LLWS is not expected through Friday night. Long Term...VFR Saturday through Saturday night. Areas of MVFR/IFR ceilings Sunday through Sunday night in association with a warm front. SFC winds should be light. Better chances of developing VFR on Monday as warm front pushes northward. However, there will be a chance of showers and thunderstorms during the afternoon as a cold front approaches. && .MARINE... Short Term... Southerly flow strengthening ahead of approaching low pressure system will necessitate SCAs with some potential for these to linger through Friday night as winds shift northwesterly and strengthen again to near SCA levels. Long Term...Small craft conditions will be possible Sunday through Monday night, especially on the ocean waters in association with an approaching low pressure system from the west that should cross the waters Monday evening. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...None. && $$ NEAR TERM...Hanes SHORT TERM...Arnott LONG TERM...Ekster
Area Forecast Discussion
National Weather Service Huntsville AL
941 PM CDT Thu May 16 2019 .NEAR TERM...(Rest of tonight) Issued at 941 PM CDT Thu May 16 2019 Thought a quiet night was ahead (except for late night fog in/near areas that recently received rainfall from convection a few hours ago). Then a storm recently formed near Holly Pond under a weak upper level disturbance; that has now drifted SE of the forecast area. This newer activity appeared to be in response to still high instability values over the region (+2000 surface based CAPE). This was mostly capped around 850mb, but lift higher up was able to overcome this and allow the more recent convection to develop. Otherwise after a rather warm day, with temperatures rising into the mid 80s to around 90 (the Muscle Shoals airport joining the 90 degree club today - with Huntsville doing that on May 8th). Output from some of the Convection Allowing Models; HRRR, HiRes ARW and NMM (especially the latter two) where hinting at more convection firing this evening over the forecast area. The HRRR was not as bullish as those two were, while the new NAM and RAP were hinting at very isolated showers. Given the recent showers and the lower level water vapor view indicating passing upper levels support, will continue isolated t-storms through midnight. As alluded to above, areas especially over much of Cullman county that received some locally heavy rains could have pre-dawn fog formation. Will put that in as well, sort of following output from MRMS rainfall data. .SHORT TERM...(Friday through Saturday) Issued at 221 PM CDT Thu May 16 2019 On Friday, the GFS seems to be keying in on residual moisture from today/tonight`s convection over AL and middle TN. This appears overdone and is yielding another potential for scattered to widespread thunderstorms on Friday within the mid-upper level ridge position. The NAM seems much more reasonable, and have kept Friday dry at this point for our area, with a better chance of thunderstorms over east central AL into GA along the higher terrain. A deeper southerly flow Friday into Saturday will also moisten low levels and diminish the steeper lapse rates we are observing today. Suggested blends appear a few degrees too low for highs on both days considering today`s temp performance thus far. So have opted to raise temps a couple of degrees both afternoons. Lows should be in the lower 60s tonight, and lower to mid 60s on Saturday morning as greater boundary layer moisture feeds into the area. .LONG TERM...(Saturday night through Wednesday) Issued at 221 PM CDT Thu May 16 2019 A cold front associated with an upper-low over the Central Plains will push east into the Mid-South region late Saturday night, and approach the Tennessee Valley heading into the day on Sunday. Models are still not totally resolving the magnitude of this feature and how far east it will make it on Sunday. Current thinking is that this feature will likely "wash out" before reaching Alabama. However, convection associated with prefrontal outflow boundaries/cold pools will likely move into the region Sunday by late morning and overspread the region during the afternoon. While cloud cover will increase steadily through the morning, enough breaks will exist (along with the strong SW flow) to enhance surface heating and low- level moisture, allowing for some appreciable instability to develop. While shear will be somewhat modest, it should be sufficient enough (along with the aformentioned mesoscale boundaries) to allow for a few organized strong to marginally severe thunderstorms -- mainly during the afternoon. Confidence is a little better in this solution and for this reason have trended PoPs high-end "chance" across most of the area to "likely" along the AL/MS border. Due to the lingering mesoscale boundaries, this activity may linger into the overnight hours on Sunday night before tapering off by early Monday morning. Thereafter, an upper-level ridge will build into the area, limiting keeping convection more isolated in nature early next week. As southwest flow deepens aloft, a humid air mass will begin to advect in as dewpoints climb into the upper 60s. This, combined with increased thickness values, would support a warming trend and potentially hot and humid weather developing by the mid to late part of next week. Thus, increased confidence exists for above normal temperatures in the far extended period with highs in the upper 80s to lower 90s. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 653 PM CDT Thu May 16 2019 Strong daytime heating had resulted in an unstable atmosphere, and development of a few showers and t-storms. Most of that activity stayed south and east of the terminals this afternoon. Cooling this evening will reduce shower chances for the overnight. VFR flying weather should continue into the late night. However, locations that received wetting rain this afternoon could experience MVFR fog/mist towards daybreak Fri. VFR weather should otherwise continue into early afternoon. More strong heating and resultant instability could initiate the formation of more afternoon convection. Given low confidence on the when/where, did not include TS in the latter portion of the TAF. && .HUN WATCHES/WARNINGS/ADVISORIES... AL...NONE. TN...NONE. && $$ NEAR TERM...RSB SHORT TERM...17 LONG TERM...AMP.24 AVIATION...RSB For more information please visit our website at
National Weather Service Wilmington OH
938 PM EDT Thu May 16 2019 .SYNOPSIS... Northwest flow aloft and southwest flow at the surface will bring together moisture and lift over the Ohio Valley this evening, resulting in an enhanced threat for thunderstorms tonight. A frontal boundary will sag slowly south across the Great Lakes region tonight into Friday, leading to a chance for showers and thunderstorms. High pressure and drier conditions will build into the region for Saturday before another front brings a chance of showers and thunderstorms on Sunday. Temperatures will continue to moderate into the weekend. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... A challenging forecast scenario continues to play out this evening, as one round of convection has exited the ILN CWA, and another is about to enter. Current surface analysis indicates that the ILN CWA remains within a general regime of SSW boundary layer flow, disrupted in part by the MCS that moved through the southwestern sections of the forecast area in the past few hours. The area is also on the edge of a significant increase in 925mb/850mb theta-e, which is advecting ENE on the southern periphery of a slightly-elevated trough over the Great Lakes. Convergence developing in this area (at the nose of the strengthening 850mb flow) has led to storm development in the IWX CWA, with storms quickly becoming strong to severe. These storms will behave much differently than the storms earlier in the day. The previous storms developed within a favorable boundary layer air mass, with overall propagation along the edge of the surface-based instability to the south, though individual storm motions were more toward the ESE. While one bowing segment was able to persist into the less favorable air mass and move into Ripley County IN (prompting a warning) eventually these cold-pool driven storms ran out of energy to tap, leading to their weakening with eastward extent. To contrast, the storms developing now are not tied at all to surface-based instability, and are instead being fed by a significant amount of theta-e advection a few thousand feet off the surface. Despite a stable layer under an inversion near the surface, these storms are realizing a decent bit of elevated instability (SPC Mesoanalysis suggests 500-100 J/kg, though it may be slightly higher given the intensity of the updrafts). Further, they are also being aided in organization by favorable shear in the 0-3km layer. It is difficult to use a model to try to project these storms, because the models simply do not have these storms developing this soon. The RAP seems to be slightly ahead of the HRRR in terms of development, which is good because it would be charitable to describe the performance of the HRRR today as poor. Nonetheless, the expectation is for overall storm motions to the E / ESE and a gradual propagation more to the SE as the LLJ continues to feed elevated instability into Ohio. The northern half of the ILN CWA will be favored (especially along and north of a line from Darke County OH to Ross County OH) with more question marks regarding any further southward propagation into an increasingly stable air mass. The primary threats appear to be large hail (with deep rotating updrafts) and heavy rain (potential training) with a much lesser threat for damaging winds (stable boundary layer). Previous discussion > Upper level energy upstream that is firing convection in nw IN will race over the CWA this late day and early evening, outpacing the low level forcing in place in western IN and IL. Near 70 dewpoints running s-n through IL will continue to get wrung out on the leading edge of this convective complex, but the upper energy outpacing it and the relative unreceptive surface features currently over ILN CWA does not favor this complex to continue to hold together as it pushes into the CWA on northwest flow aloft. This is just a mashup of a couple of vastly differing model solutions this evening, most of which keep convective initiation at bay and more northwest of the CWA through this evening. Expect some storms in northern Ohio to lay out a boundary wnw to ese over the CWA and another round of storms possible early in the overnight period northwest of metro Dayton. Any storms overnight will be on the decrease in both coverage and intensity, dying out towards daybreak. Storms that are present will have enough shear to maintain a presence for at least a few hours early tonight, and possibly but less likely through the overnight period. This shear increases the threat of these storms to produce large hail if they are present, which remains in high question at this time. Overnight lows were raised, particularly in the western third of the CWA where dewpoints in the mid 60s should be working in and inhibiting any rapid temperature decreases. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/... A relative minimum in thunderstorm activity is expected to start the day on Friday, but this could ramp up into some storms by late morning given the boundary that is expected to cross the CWA and potentially act as a focus for more storms to fire on. The bulk of the model solutions push the area of rain to the northeast sections of the CWA while the CAMs fire more robust activity along the boundary by later afternoon. Played the middle ground here and had a brief uptick in the potential for thunderstorms running from nw of Dayton to se of Columbus late in the day, decreasing sharply with the setting sun tomorrow. Any activity tomorrow night will lift well northeast of the CWA overnight. Highs on Friday were cut slightly everywhere given the expected cloud cover and potential rain, but by 3-4 degrees in the north where these conditions are more likely. Overnight lows will again be mild - 60-65 with the warmer readings southwest of Cincy and coolest northeast of Columbus. Forecast probabilities of thunderstorms are unusually low confidence starting in the immediate near-term and lasting through Friday given the wholesale differences between models, until the upper ridge finally begins to build into the region and southwest flow aloft turns more westerly overnight. && .LONG TERM /SATURDAY THROUGH THURSDAY/... A mid level ridge will continue to build northward across the region on Saturday. This will place our area in a somewhat humid and warm airmass. There could be a low chance of a PoP up shower or storm during the afternoon, but that`s around 10 percent so have kept the forecast dry. Highs will be in the lower to mid 80s. For Saturday night into Sunday, a mid level trough with embedded short wave energy will pivot northeast from the central/southern Plains toward the western Great Lakes and middle Mississippi River Valley. This system now seems to have a stronger surface low and overall stronger wind field. The mid level ridge will move east on Sunday while the mid level trough/embedded energy pushes a cold front east. The timing of the front and associated instability will play an important part as to whether we see much severe weather Sunday afternoon and evening. For now, it looks like the slower progression of the cold front and max diurnal instability favor points just to our west, and that is where SPC has a slight risk for scattered severe storms. But given strong wind field and at least early on low end moderate instability across our west, there will likely be a marginal risk for isolated severe. A little early to put in the HWO for now. Otherwise, given the strong wind field and diurnal mixing, it will be breezy to windy with the windier conditions slated across the western CWFA. After lows in the 60s, Highs will range from the upper 70s northwest to the mid 80s east. As the mid level trough pushes northeast across the remainder of the Great Lakes Sunday night into Monday, the cold front will push east as well. Instability wanes fairly quickly overnight, such that only some scattered showers are expected across the east by morning. Any lingering pcpn should move out of eastern locations by afternoon with skies becoming partly cloudy. After lows from the upper 50s northwest to the mid 60s east, highs will range from the lower 70s northwest to the lower 80s southeast on Monday. High pressure at the surface and aloft is expected to move into the region Monday night, then move east on Tuesday. This should provide a window of dry weather with near or slightly above normal temperatures. The remainder of the extended is still muddled with uncertainty (in terms of timing) as we head into mid to late week next week. A warm front will likely move into the region on Wednesday followed by a cold front Wednesday night into Thursday. Have kept a chance of showers and thunderstorms in the forecast during this period. Highs will remain in the 70s to the lower 80s. && .AVIATION /02Z FRIDAY THROUGH TUESDAY/... In the next hour or two, some rain (possibly with embedded thunder) will impact the KCVG/KLUK airports. However, prevailing conditions should remain VFR. There may also be some brief wind gusts out of the west at about 25-30 knots. VFR conditions should prevail for all TAF sites going into the overnight hours, but there will be another chance of storm development after 04Z at KDAY and especially KCMH/KLCK. For now, it remains unclear if the storms will actually impact the airports, but some MVFR/IFR conditions will be possible if they do. A period of VCTS has been included at these TAF sites for the most likely timing. Also, some MVFR ceilings may get into KCMH/KLCK during the morning hours, but these should dissipate by early afternoon. Thunderstorms will again be possible on Friday afternoon for KILN/KDAY/KCMH/KLCK, mainly from 20Z onward. Otherwise, VFR conditions are expected, with westerly winds of 10-12 knots and SCT/BKN cumulus. OUTLOOK...Thunderstorms may continue into Friday evening. Thunderstorms will be possible again on Sunday. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...None. KY...None. IN...None. && $$ SYNOPSIS...Franks NEAR TERM...Franks/Hatzos SHORT TERM...Franks LONG TERM...Hatzos AVIATION...Hatzos
Area Forecast Discussion...UPDATED
National Weather Service North Platte NE
727 PM CDT Thu May 16 2019 .UPDATE... Issued at 726 PM CDT Thu May 16 2019 A blend of the HRRR, RAP, HREF and previous forecast is in place which produces the best rain chances across swrn Nebraska where storms are beginning to organize. This storm activity should lift northeast toward ncntl Nebraska this evening. The HRRR updraft helicity product suggests a continued chance for strong to occasionally severe storm development. && .SHORT TERM...(This evening through Friday night) Issued at 409 PM CDT Thu May 16 2019 The primary forecast challenge over the next couple days is regarding a surface low centered around the NE/KS/CO point with a quasi-stationary front wiggling eastward across southern/central Neb and a dryline extending to the south. This setup favors a double shot of severe weather for western Neb... one this evening and another on Friday. Another concern is the temperature forecast as a large gradient sets up for Friday with highs in the 50s north of the front to 80s south. This evening and tonight... Convective initiation is underway across the western Neb panhandle as of 20z. Spread PoP east through the evening as further development and intensification is expected along and north of the stationary front. Coverage through the early evening hours will remain rather limited with surface dew point depressions over 30F across SW Neb and at least 20F north. Supercells are the favored storm type due to iso/sct nature, somewhat veering wind profile, modest deep layer shear, very steep lapse rates, and ample instability as indicated by the 20z LBF RAOB. Large hail appears to be the main threat with decent CAPE in the hail growth zone and weak shear in the low levels and fairly high LCL`s (mitigating the tornado threat). Added convergence and forcing from the LLJ will help transition the convection into multicell clusters toward dark. Hail will continue to be the concern overnight with any elevated storms across northern Neb under upslope flow and better moisture advection. Friday... The severe threat intensifies across the CWA as the heart of the negatively-titled upper trough emerges from the Rockies and the H3 jet noses into the central High Plains. Frontogenesis increases remarkedly at the surface and in the mid-levels. The low level moisture draw remains strong, but the advancing dry line and strengthening cold front increase the convergence. The front`s placement will be key in determining the area greatest at risk for severe weather, particularly the tornado threat. Guidance has been fairly consistent in progging southwest into north central Neb as the hot zone, mainly from IML to LBF to BBW. Most guidance has the cap eroded around 21z. CAMS suggest isolated supercells to begin across SW Neb, merging into a cluster or perhaps MCS/MCV later on farther northeast. This makes sense given the mean wind being close to parallel with the boundary and the wind profile eventually becoming nearly unidirectional. In the meantime, forecast soundings suggest significant CAPE (over 3000 j/kg) and shear (20 kts of 0-1km and at least 50 kts of 0-6km) with ample low level helicity, also noted in a greatly veering wind profile and sickle-shaped hodographs. Model analogs also hit on active tornado days for western/central Neb over the past 20 years. Very large hail will also be possible with these storms given fat CAPE and seasonable freezing levels. As the supercells merge, deep layer shear remains strong, increasing the damaging wind potential. The LLJ will be focused more toward central/eastern Neb, but hail will still be possible with elevated convection in the cool sector. The flooding threat also cannot be overlooked. Forecast PWATs are near the 90%ile of climo, and the wind profile with boundary positions favor training storms. Another forecast concern is the effect of tonight`s convection on boundary locations. Synoptically, this pattern is one of the most favorable for intense weather in recent years. .LONG TERM...(Saturday through Thursday) Issued at 409 PM CDT Thu May 16 2019 The upper trough axis bisects the High Plains on Saturday and the closed low meanders across the northern Plains through Sunday. With Nebraska being on the cooler side of the surface boundary at this point, the severe potential decreases, especially heading into Sunday when highs struggle to leave the 50s and 60s. Left scattered thunder in for Saturday with highs near 70 and sufficient instability. Another potent trough and upper low take aim on the area Monday into Tuesday. This time, the system takes a more southern route with the low sitting right over the Sandhills. Temperatures will be more reminiscent of early spring and precip will be rain showers during the day and possibly rain/snow mix at night. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 625 PM CDT Thu May 16 2019 Scattered showers and thunderstorms continue to develop across western and southwest Nebraska this evening. Thunderstorms will continue developing and moving northeastward through the evening and overnight hours. Expect thunderstorm development to hold off until late evening across north central Nebraska so did adjust the timing of vicinity thunderstorms for KVTN later by several hours. Winds will remain breezy through the evening and overnight hours out of northeast. Winds will shift to the southeast across southwest Nebraska tomorrow afternoon ahead of the frontal boundary. Areas behind the front, mostly across the northern Sandhills and north central Nebraska will see lower cloud ceilings tomorrow morning through the afternoon leading to IFR conditions. && .LBF WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...CDC SHORT TERM...Snively LONG TERM...Snively AVIATION...Gomez
Area Forecast Discussion
National Weather Service Louisville KY
1032 PM EDT Thu May 16 2019 .Forecast Update... Issued at 1032 PM EDT Thu May 16 2019 MCS continues to move to the southeast, heading into southeastern Kentucky. Recently surface gusts have only been in the 30-40mph range as the strongest winds remain aloft. Still, brief very heavy rain and dangerous lightning will continue to be a threat with this system as it moves through. Storms have rapidly developed this evening along a surface front from Nebraska to Ohio. The majority of this convection is expected to remain to our north, associated with low level jets over the middle Missouri Valley and reaching from Illinois to Ohio, but southeast Indiana and the northern Blue Grass could get grazed during the pre-dawn hours given ESE 850-300mb flow. Issued at 552 PM EDT Thu May 16 2019 Keeping an eye on an MCS and a supercell to our north diving southeastward. The original complex, now moving through the Indianapolis metro, had been struggling to produce much more than pea sized hail. Recently though it has begun to bow out and there have been gusts of 60 mph on the north side of Indianapolis. As this complex continues to head southeast it will enter an air mass that is more stable with less moisture in the column and weaker mid-level lapse rates. Nevertheless, will need to keep an eye on this convection as it may clip Jefferson County Indiana. Its forward motion has increased in the last half hour as its gust front pushes forward, so timing is tricky, but at its current movement it could be in or near the Madison area between 6:30 and 7:30. By then it will likely be in a weaker condition that it is now, but will still be capable of gusty winds and small hail. A supercell developed earlier near Danville, Illinois, west of the main complex. That cell is located in a much more unstable atmosphere with stronger CAPE, much higher PWAT, and steeper mid- level lapse rates. On its current trajectory it could reach northern Washington County Indiana around 8pm according to the latest radar animation. Take that timing and positioning with a large grain of salt, though, as the storm is still quite a distance away and much could change, especially if the storm bows and accelerates. These storms may still pack a punch as they enter southern Indiana, but should weaken as they approach the Ohio River. As the sun sets CIN will increase and SPC RAP shows the significant hail parameter decreasing. We spoke with SPC earlier and they too felt that the convection should begin to lose some of its intensity this evening as it moves southward. Still, it will be important to keep an eye on them as they approach. && .Short Term...(This evening through Friday) Issued at 300 PM EDT Thu May 16 2019 ...Isolated strong storms possible this evening and tonight... Current radar imagery shows an MCS in IL that is expected to affect IN/OH and portions of KY shortly after sunset. Aside from some temporal disagreement, multiple hi-res models have isolated showers and thunderstorms developing across our CWA, so decided to carry slight chances during the overnight hours. Gusty winds, hail, and heavy rainfall will be possible in the stronger or severe storms, with the best chances for severe weather across northern portions of the region. Overnight lows will stay warm from SW flow, and are only expected to fall into the mid 60s. Friday will be very warm and dry as a ridge begins to build in from the west. As a result, highs are forecast to climb into the upper 80s and even into the low 90s in urban metro areas. Dewpoints will be in the upper 60s as well, so Friday looks to be quite muggy! .Long Term...(Friday night through Thursday) Issued at 312 AM EDT Thu May 16 2019 Friday through Saturday Night... By Friday morning, we`ll be on the periphery of the Gulf ridge with a likely band of showers and storms moving from northern IL through IN and OH and into WV. Throughout the day, the ridge is expected to strengthen and this should limit our convective coverage for the day. Latest guidance suggest it will be a warm and humid day with highs topping out in the mid-upper 80s. If enough insolation occurs, we could hit 90 in the Louisville metro area Friday afternoon. Dry and muggy conditions are expected for Friday night with lows in the mid-upper 60s. Ridge axis should continue to build northward slightly on Saturday resulting in another warm and muggy day with highs solidly in the mid-upper 80s. Lows Saturday night will remain in the mid-upper 60s. Sunday through Wednesday... By Sunday morning, the ridge axis is forecast to break down to our west while a mid-level wave and associated surface low and frontal boundary approach from the west. As this feature pushes eastward, it will pose a threat of severe weather from the Plains and into the Midwest. However, as it approaches our area, the moisture transport with the system is sufficiently less. Despite the lesser degree of moisture, combination of synoptic scale lift and frontal lift should result in scattered showers and thunderstorms moving through the region on Sunday. Some storms could be strong with damaging winds being the main threat. Frontal boundary may take its time moving through the region as becomes stretched out and perhaps even occluded. Thus, some chances of showers and storms seems reasonable across our eastern sections on Monday, with a decidedly drier pattern evolving from west to east throughout the day. The upper pattern looks to reamplify a bit on Tuesday as another strong trough pushes into the Plains. Downstream, we`ll see ridging over our area which should result in a slightly drier pattern for Tuesday. Aforementioned Plains trough is forecast to move eastward and may impact our region around Wednesday. Just as in the weekend system, the moisture transport with this system appears to weaken as the boundary heads into the Ohio Valley. Though, enough lift and upper dynamics suggest at least another round of showers and storms on Wednesday. Temperatures through the period will remain quite warm with daily highs in the in the low-mid 80s with overnight lows ranging from the upper 50s to the lower 60s. && .Aviation...(00Z TAF Issuance) Updated at 712 PM EDT Thu May 16 2019 Storms over southern Indiana will continue to cruise to the southeast but are expected to weaken as they do so. SDF and LEX will stand the best shot at storms this evening, along with the possibility of a gust front bringing gusty northwest winds just ahead of the storms. Overnight convection will continue to diminish, but some LLWS will be possible, especially at SDF and LEX, on the edge of a low level jet from Indiana into Ohio. Tomorrow should provide uneventful weather, other than some slightly gusty afternoon winds, with upper ridging building overhead. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...None. KY...None. && $$ Update...13 Short Term...SSC Long Term...RJS Aviation...13
Area Forecast Discussion
National Weather Service Pendleton OR
743 PM PDT Thu May 16 2019 .SHORT TERM...Upper low moving slowly across southern Oregon this evening with a southeast flow of moisture over the forecast area. Band of heavier rain that moved through the region earlier today has pushed north into Washington. Precipitation has diminished for most locations. Radar indicates a circulation center vicinity Columbia basin and Yakima valley with enhanced showers. Models pick up on this and generate additional rain across the basin into the northeast Oregon mountains overnight. The main upper low will continue to move east into Idaho on Friday. Rain over the eastern portion of the forecast area through afternoon decreasing by evening. Break in the active weather Friday night and early Saturday with weak ridge overhead. 94 && .PREV DISCUSSION... /issued 426 PM PDT Thu May 16 2019/ SHORT TERM...Tonight through Sunday...Latest radar and satellite imagery show a band of rain showers extending SE-NW from SE Oregon NWWD to the East slopes of the Washington Cascades. Isolated weak thunderstorms with some CG Lightning have developed over nrn Oregon and SRN WA early this afternoon. The radar representation of these storms has been rather poor thus far with extensive cloud cover limiting instability despite decent vertical shear. Latest HRRR suggests that this band of showers will lift northward into Washington this evening with the TSTM threat exiting all of the forecast area by 03Z. Showers are expected to redevelop over the eastern mountains later this evening and overnight. This is where the heaviest QPF is likely to be with amounts exceeding 1 inch possible by Friday morning. East slopes of the Washington Cascades could also see amounts of 1 inch or more by Friday morning. More rain is likely across the eastern mountains during the day Friday before tapering off Friday night. It will be mostly dry Saturday in between storm systems then another storm will move in during the evening with more rain through Sunday. It will be breezy to windy across the lower elevations on Friday especially during the afternoon with west winds of 15-30 mph and some higher gusts. LONG TERM...Sunday night through next Thursday...Unsettled weather is expected throughout the long term period and an upper trough will remain over the western states. The trough will be centered over our area initially with a closed low over northern California. This will give us a chance of rain Sunday night with as much as a half inch of rain in the mountains and up to a quarter inch in the lower elevations. Monday will see the closed low move into Idaho while a second low approaches the coast. This will continue a chance of rain in the mountains and a slight chance in the lower elevations. The second low will move ashore but will be further south than the first one. The trough axis will be to our east as well. This will continue the chance of rain in the mountains and a slight chance in the lower elevations for Monday night through Tuesday night. Models begin to differ at this point and some show a drying out while others keep some showers. With the low in the desert southwest by Wednesday, have kept chance of showers in the mountains Wednesday tapering off to a slight chance late Wednesday night and Thursday while the lower elevations are mainly dry. Temperatures will be mainly in the upper 50s and 60s Monday through Wednesday then perhaps a couple of degrees warmer on Thursday. Perry AVIATION...00Z TAFs...Low pressure to our south will send rain showers through the area tonight through tomorrow morning. Moderate rain will be possible at times this evening. Have generally kept ceilings at MVFR levels but occasional MVFR ceilings and visibilities will be possible with the heavier rain showers. There is enough instability for a few thunderstorms over the northern portions of the area late this afternoon so have added a TEMPO for TSRA from 22Z-02Z to KPSC. Do not have enough confidence to add it to other TAF sites. Winds will begin increasing this evening from 5 to 15 kts and will reach 15 to 25 kts with gusts to 25 to 35 kts after 15Z. Perry HYDROLOGY...Copious amounts of rain are expected tonight from central and northern Oregon into south central and southeast Washington. Rainfall amounts of 1-1.5 inches are possible by Friday morning for the Blue and Wallowa Mountains and the east slopes of the Washington Cascades. Rain will taper off on Friday but upslope flow into the eastern Mountains could result in another .5+ inches before ending Friday evening. More rain is expected Saturday night through Sunday night with heaviest amounts over the eastern mountains. The Flood watches currently posted remain in effect and a Flood Watch has also been issued for the Imnaha River in Wallowa County. 78 && .PRELIMINARY POINT TEMPS/POPS... PDT 48 59 42 70 / 80 70 10 10 ALW 50 60 45 72 / 80 80 20 0 PSC 54 66 47 74 / 70 60 0 0 YKM 51 63 42 70 / 70 50 0 0 HRI 51 64 45 74 / 70 60 0 0 ELN 49 57 40 66 / 80 60 0 0 RDM 42 58 37 65 / 60 30 0 20 LGD 45 53 38 65 / 90 80 20 10 GCD 43 55 35 65 / 80 70 0 10 DLS 51 63 45 73 / 60 30 0 10 && .PDT WATCHES/WARNINGS/ADVISORIES... OR...Flood Watch through Saturday morning for ORZ049-050-502-507. WA...Flood Watch through Saturday morning for WAZ029-030. Flood Watch until 5 AM PDT Friday for WAZ026-520. && $$ 94
Area Forecast Discussion
National Weather Service Raleigh NC
920 PM EDT Thu May 16 2019 .SYNOPSIS... Bermuda high pressure will hold off the Southeast coast through the weekend. A strong upper level high will develop across the Southeast on Friday and continue through the weekend, producing hot and largely dry conditions. && .NEAR TERM /THROUGH TONIGHT/... As of 920 PM Thursday... Another very tranquil weather night across central NC as high pressure was in control. There were some cirrus noted over WVA and VA spreading south over NC. However, these cirrus were thin and appear to be limited in coverage. The temperatures were already in the upper 50s NE NC ranging into the lower 70s south and in some of the urban centers at mid-evening. Dew points are creeping up into the 50s (but still not into the uncomfortable range, yet). Expect some cirrus tonight, but the latest IR and WV satellite data strong suggests it to be scattered and thin for most of the night. Lows should settle into the lower 50s NE ranging to near 60 along the southern tier of counties along US-74. MCS activity upstream just SW of Cincinnati is moving south and dissipating this evening, posing no threat to NC. Additional thunderstorms were developing in the favorable "ridge runner" position. Models, especially some of the CAMS suggest that one or more of these areas of convection may congeal into MCS(s) tonight into Friday and track toward the central Appalachians and Tennessee Valley. If our dew points can recover into the 60+ range on Friday, there should be sufficient CAPE with strong heating (highs in the 80s) to support some afternoon or late day remnant storms. && .SHORT TERM /FRIDAY AND FRIDAY NIGHT/... As of 255 PM Thursday... Temps will continue to warm above normal with the Bermuda ridge in place, weak surface troughing through the Piedmont, and rising heights aloft as mid level ridging builds in from the W. Based on forecast thermal profiles with warm air aloft and good diurnal mixing, highs in the upper 80s to lower 90s look reasonable, on the warm side of statistical guidance and in line with consensus thicknesses rising into the 1420s. Precip chances/coverage still appear small but not zero. The aforementioned MCV is expected to sweep by just to our N or across extreme N/NE NC early Fri, potentially sweeping a weak boundary through central NC through early afternoon. PW is projected to rise above normal, and forecast soundings from the NAM/GFS indicate sufficient moisture and steepening lapse rates aloft for electrification, although coverage is likely to be limited as the ridge builds aloft. Deep layer bulk shear appears marginal at just 20-25 kts, however the latest model runs indicate moderate MLCAPE through the afternoon. Following the HREF mean depiction, will mention isolated storms Fri, mainly across the NW and far N early, translating into S and SE sections in the afternoon. A second weak wave (likely spawned from upstream convection) is noted by the RAP crossing VA and NE NC late Fri into Fri night, and this may trigger additional isolated storms across far N and NE sections after nightfall as this energy feeds on residual elevated marginal CAPE. Expect mild lows in the mid-upper 60s under partly cloudy skies. -GIH && .LONG TERM /SATURDAY THROUGH THURSDAY/... As of 240 PM Thursday... Saturday and Sunday: The sub-tropical ridge aloft will gradually shift eastward from over the Mid-Atlantic and Southeast regions on Saturday to offshore by Sunday. An upper level shortwave will swing through the Plains/Midwest and toward the western Great Lakes through Sunday night. At the surface, the piedmont trough will weaken over central NC on Saturday. The surface high will build westward toward the region resulting in southerly return flow aiding the advection of warm air into the area. Will continue to keep the forecast dry through Sunday night. Highs in the upper 80s to mid 90s and lows in the mid to upper 60s Sat/Sat night. Thankfully min RH values will be in the 40s and heat indices are not expected to be an issue. Slightly lower highs on Sunday with similar overnight lows expected. Monday through Thursday: While there is good agreement between the models with respect to the overall weather pattern, there is some uncertainty with respect to how that will translate in terms of precipitation across central NC. As the surface low races off to the northeast through New England/eastern Canada, the trailing cold front will pivot to more west-east orientation, slowly sliding into the region Mon/Tue. There could be some resulting showers and thunderstorms Mon/Tue (should they hold together/re-develop in the lee of the Appalachians), best chances will be farther west. The parent upper level trough should move offshore as the sub-tropical ridge once again builds into the region mid-week. The surface front may briefly stall over the Carolinas/VA before lifting northward once again as a warm front. Southwesterly flow at the surface will continue to advect warm, moist air into the region through the middle of the week, resulting in fairly persistent temperatures, with highs in the upper 80s to low 90s and lows in the mid to upper 60s. && .AVIATION /00Z FRIDAY THROUGH TUESDAY/... As of 730 PM Thursday... High confidence of VFR conditions through the TAF period. As a disturbance moves into the area from the northwest there is a slight chance of a shower or two at northern terminals by late Friday morning into the afternoon. Otherwise no restrictions to flight conditions are expected. Winds will be out of the southwest at 5-10 gusting to 15 kts by afternoon. Long Term: A chance for sub-VFR conditions with increasing moisture Sunday morning. The next chance for shower and thunderstorm activity would be late Monday into Tuesday but confidence is low at this point. && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Badgett NEAR TERM...Badgett SHORT TERM...Hartfield LONG TERM...KC AVIATION...Ellis