Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/26/22

Area Forecast Discussion
National Weather Service Gray ME
1148 PM EDT Mon Apr 25 2022 .SYNOPSIS... A slow moving front will approach the area Tuesday and bring scattered showers during the day. A wave of low pressure will develop along the front and move north into the Gulf of Maine. This will increase the chances for showers or rain near the coast Tuesday night, with the storm eventually slowing to a crawl around the Bay of Fundy. That will leave the weather unsettled through the remainder of the work week along with cooler temperatures. && .NEAR TERM /TONIGHT/... 1150 PM Update... Blended in the latest HRRR runs which best capture cooling temps and increasing Tds in onshore flow over most of area... besides in the shadow of the mountains over the Connecticut River Valley extending over into the Rangeley Lakes region. At this hour... stratus is beginning to fill in along the I95 corridor with this trend expected to continue through about dawn. 855 PM Update... Very little change to the near term portion of the forecast with the HRRR continuing to capture T/Td trends well this evening in onshore flow. Made some tweaks to PoP/Wx/QPF as a weakening front pushes into the region late tonight into tomorrow. Otherwise, will be looking for evidence of low-level marine moisture coming ashore, and for any fog and/or stratus formation... particularly over the I-95 corridor and toward the coast. Previously... Onshore flow continues to bring a cooler and more moist maritime airmass into the region from east to west. This flow direction will likely also bring with it some patchy fog and low clouds along the coastline, as well as areas east of the foothills across Maine. High and mid level clouds will also continue to stream across the region, gradually becoming thicker through the overnight hours. As a weakening cold front slowly approaches from the west, a few showers will likely reach northwestern areas by daybreak tomorrow. && .SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/... Tomorrow`s weather will be dictated by a weakening cold front slowly crossing through the area. The precipitation associated with it will also be weakening as the forcing wanes, resulting in scattered showers that are generally light to occasionally moderate passing through in the morning to early afternoon hours. Then by late in the day, low pressure is expected to begin to develop and deepen in the Gulf of Maine along the front. This cyclogenesis brings an enhanced chance for precip along the coast, and continues into tomorrow night. The chance for showers continues along the coastal plain through daybreak Wednesday morning, while western areas generally dry out through the night. The system is too warm for any accumulating snow through Tuesday night, with the best chance for any flakes mixing in being across the highest peaks. QPF amounts also look to remain light, with most areas expected to pick up between 0.10-0.25in && .LONG TERM /WEDNESDAY THROUGH MONDAY/... A weak area of low pressure will exit from the Gulf of Maine to eastern sections of the Pine Tree State Wednesday morning. This will allow for steady light rain along over southern sections to lift out of the area. However, significant height falls will cross the region in the wake of this system. Plenty of clouds will result along with scattered rain showers and cool conditions. The highest chance for rain will be over northern and eastern portions of the forecast area. The 12Z model suite and ensemble solutions remain in relatively good agreement allowing for continued cyclogenesis Wednesday night and Thursday near the Bay of Fundy. This will increase the pressure gradient across the region and have upped the wind forecast from most available guidance. Cut-off low season will be in full swing as well with a dynamic upper level system crossing the region through the end of the work week. This will allow for more scattered showers across the region. Snow showers will fall across northern areas as cold air wraps in behind the system during the mid and late work week period as well. There could be some accumulations of snow which is supported by the latest ensemble solutions. While much of the Eastern Half of the CONUS remains mild, New England will be featured with below normal temperatures with H8 readings in the -4C to -6C range. This will last into the start of the weekend. && .AVIATION /04Z TUESDAY THROUGH SATURDAY/... Short Term...Ceilings gradually lower through the overnight hours, with most terminals falling into MVFR conditions by tomorrow morning. Coastal terminals and AUG will likely experience periods of IFR conditions due to low stratus tonight and tomorrow. Most other terminals hold onto MVFR ceilings tomorrow, and some scattered showers are possible at times at all terminals. Ceilings then lift to VFR across New Hampshire terminals tomorrow night, but Maine terminals hold onto MVFR to IFR conditions through Wednesday morning. Long Term...Low pressure will begin to lift northeast Wednesday morning, allowing for a period of rain and IFR conditions to exit the region. However, scattered showers from an upper level low pressure system will bring periods of MVFR conditions in scattered showers for the rest of the work week. Some snow shower activity can be expected in the mountains. Winds will become gusty at all sites beginning Wednesday night. && .MARINE... Short Term...A weakening cold front approaches from the west, bringing increasing southerly flow to around 20kts. Low pressure begins to develop in the Gulf of Maine Tuesday night. Long Term...Winds will begin to gust Wednesday night as flow turns offshore. SCA conditions are likely through the end of the week...and may be strong SCA conditions Thursday. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...None. && $$ UPDATE...Casey NEAR/SHORT TERM...Clair LONG TERM...Cannon
Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
1030 PM CDT Mon Apr 25 2022 .UPDATE... Issued at 824 PM CDT Mon Apr 25 2022 Cool, dry high pressure continues to build into the region this evening. Some high clouds persist across the eastern part of the forecast area while elsewhere the sky is clear. Temperatures tonight will drop into the 30s for most of the area and the current Freeze and Frost headlines cover this threat well. High pressure slowly crosses the area tomorrow, though, with light winds and a clear sky expected again tomorrow night. Because of this, temperatures will be similar or perhaps even cooler tomorrow night as winds will likely be even lighter as the center of the surface high crosses the region overnight. Much of the area will have a chance at another frost tomorrow night, but the eastern part of the area has the greatest risk as the clear and calm conditions are most likely there. With this update we have lowered temperatures tomorrow night and introduced the chance for another frost. Kimble && .SHORT TERM... (Through Late Tuesday Night) Issued at 254 PM CDT Mon Apr 25 2022 The cold front that affected the area with showers and thunderstorms yesterday continues to march southeast into the Tennessee Valley this afternoon. Cold air advection is in full force with 850 mb temperatures around 0C (+/-5) covering the forecast area. Temperatures have behaved right in line with forecast expectations with surface observations largely in the 50s at 19z. Visible satellite imagery shows thicker cloud cover lining the front to the southeast with gradual clearing further northwest. Mid to upper flow remains southwesterly, which continues to carry a few high clouds overhead. High cloud cover has impeded some of the diurnal potential from developing the cu field that can be seen in areas over northern Missouri into western Illinois, coinciding with some remnant mid-level moisture that continues to slowly depart with the exiting system. RAP analysis of the 700 mb level shows drier air continuing to eat into this layer, along with surface high pressure building in from the central plains. The clearing trend will continue, albeit gradual. Given the sunshine and deeper mixing of the afternoon, areas have gusts of 20-25 knots, mainly along and north of I-70. As high pressure works in from the west and the sun sets, gusts will subside this evening with winds generally relaxing to around 5 knots or less. Clearing skies and light wind will result in more efficient radiational cooling, making for a chilly night. Temperatures in the 30s are expected to result in frost over parts of the area with near/slightly below freezing temperatures running through northeast Missouri and west central Illinois. The main change from earlier forecasts is to add portions of southeast Missouri to the frost advisory with higher confidence in cooler temperatures. This includes Crawford/Washington Counties in MO, joining with points to the north and east, in addition to Madison County in Illinois. This does not include the metro, however, as urban warmth will be enough to keep temperatures in the upper 30s. Conditions will remain cooler than normal through Tuesday. High pressure and sunshine should make it a pleasant day otherwise with highs similar to today`s temperatures. While lows fall off into the 30s Tuesday night, it should be a touch warmer, which will keep frost out of the forecast. Maples .LONG TERM... (Wednesday through Next Monday) Issued at 254 PM CDT Mon Apr 25 2022 The general trend will support near normal temperatures from midweek through the end of the period. There is increasing potential for rainfall from late Wednesday night into next weekend. However, details in timing and spread will be dependent on details that remain less clear due to decreasing model consensus in time. Surface high pressure will begin to depart to the east Wednesday with return surface flow commencing underneath mid/upper ridging. Wednesday is expected to remain dry but warms up with southwest 850 mb flow transporting 5-8C air northeast into the region. In conjunction with the sunshine, high will return to the mid-60s to low-70s. Long range guidance continues to hint at a shortwave progressing west to east within the northern periphery of the upper level ridge. Surface ridging extends south of a strong surface high, from the Great Lakes Region into the Tennessee Valley, turning surface flow out of the southeast through the day Thursday. Though mid-level moisture begins to increase, dry air feeds in from the east around the ridge with drier air entrenched in the lowest 10-15k feet. The main question Thursday will be how well this dry layer holds, while moisture attempts to work in from the west. While NBM blends encompass the area with some level of precipitation probabilities, I believe there is enough evidence to limit confidence in how far east this potential spreads. For now, better support is likely from central Missouri westward late Thursday as moisture deepens ahead of a modest low level jet and underneath the upper level ascent. Ensemble spread persists into next weekend. The main culprit will be a deepening surface low running ahead of an upper level trough that tracks into the Plains. Another shortwave ejects east through the upper ridge, ahead of the main system, introducing better chances for showers/thunderstorms Friday. The main concern will likely arrive over the weekend as the upper trough and deepening surface low tracks into the Midwest. This pattern is more conducive for thunderstorm potential, which will have to be fine tuned as there is better consensus in time. Maples && .AVIATION... (For the 06z TAFs through 06z Tuesday Night) Issued at 1022 PM CDT Mon Apr 25 2022 Light winds and VFR conditions expected tonight. NW winds could gust to 15 to 20KT at times tomorrow around midday, but this will be diminishing in the evening as high pressure brings another calm night Tuesday night. Kimble && .LSX WATCHES/WARNINGS/ADVISORIES... MO...Frost Advisory until 8 AM CDT Tuesday for Audrain MO-Boone MO- Callaway MO-Cole MO-Crawford MO-Franklin MO-Gasconade MO- Lincoln MO-Moniteau MO-Monroe MO-Montgomery MO-Osage MO- Pike MO-Ralls MO-Saint Charles MO-Warren MO-Washington MO. Freeze Warning until 8 AM CDT Tuesday for Knox MO-Lewis MO- Marion MO-Shelby MO. IL...Frost Advisory until 8 AM CDT Tuesday for Bond IL-Calhoun IL- Fayette IL-Greene IL-Jersey IL-Macoupin IL-Madison IL- Montgomery IL-Pike IL. Freeze Warning until 8 AM CDT Tuesday for Adams IL-Brown IL. && $$ WFO LSX
Area Forecast Discussion...UPDATED
National Weather Service Shreveport LA
956 PM CDT Mon Apr 25 2022 .UPDATE... Light rain is still ongoing in a few locations southeast of a line from Southern Sabine County to Monroe. Latest radar loops show the precip continues to gradually diminish and should end in most locations near or shortly after midnight, which is also support well by model guidance. I did retain some slight chance PoPs across the far southern zones through the overnight hours as an upper trough axis is still to the west of Oklahoma and Texas and will move across the forecast area during the overnight hours. However, low-level dry air advection may prove to be too much to overcome and may finish scouring out the moisture availability. Main update to the grids was to trim PoPs through the rest of the night based on the above reasoning. Some minor edits were also made to the hourly temperature and dewpoint grids based on the latest obs. Updated text products have been sent. CN && .PREV DISCUSSION... /issued 641 PM CDT Mon Apr 25 2022/ AVIATION... For the 26/00z TAFs, a band of showers continues to affect terminals south of a line from KJSO to KMLU. The rain will continue to gradually exit the area and should end by 26/06z. No additional precipitation is expected at the TAF sites beyond this time. Ceilings will continue to be somewhat variable resulting in flight conditions in the VFR range north of a line from KTYR to KTXK, to KELD, but ceilings in the MVFR/IFR range farther south. VFR flight conditions will gradually return from north to south as the rain exits the area and northerly winds bring drier air into the region. Northeasterly winds will increase to between 10 and 15 kts, with a few gusts near 20 kts, during the daytime hours of Tuesday. CN PREV DISCUSSION... /issued 304 PM CDT Mon Apr 25 2022/ SHORT TERM.../Tonight through Tuesday Night/ The latest mid-level analysis indicates multiple weak short waves moving from Central Texas into Louisiana. The area is in a southwesterly mid-level flow ahead of a broad trough crossing the central U.S. At the surface, a cold front is now south of the area. The front is well-defined on radar and satellite with numerous showers and scattered thunderstorms. At 850mb, the front is still straddling the ArkLaTex with scattered showers mostly across areas along and south of I-20. Tonight, the 850mb cold front will continue to slide southeastward of the area as showers continue to mostly decrease in coverage. The SPC HREF supports that forcing from a second short wave will push across the area later this evening into the overnight and contribute to a prolonged period of showers with isolated embedded thunderstorms for areas south of the I-20 corridor. Tuesday into Tuesday night, forecast sides with the SPC HREF with a cold front pushing southeast of the area and high pressure building in from the north early in the day Tuesday. Thus, a few showers and possibly an isolated thunderstorm will be possible early in Deep East Texas and central Louisiana before precipitation comes to an end altogether. The area will clear from the northwest with mostly sunny or sunny skies across most of the area by Tuesday afternoon. Skies will remain clear Tuesday night as high pressure continues to build in with drier air from the north. Temperatures are continuing to trend a few degrees below most model guidance and the HRRR seems to have a pretty good handle on this so sided with it through the overnight hours. Lows tonight will range from the upper 40s north of the I-30 corridor to the upper 50s in portions of Deep East Texas and central Louisiana. After that, forecast is closest to the National Blend of Models (NBM). Highs on Tuesday will range from the lower to mid 70s across the area with lows tomorrow night in the mid to upper 40s. /04-Woodrum/ LONG TERM.../Wednesday through Monday/ Ridging will dominate the Four State Region`s weather pattern through the end of the work week. Establishing itself further as Wednesday begins, said ridge will amplify along an axis extending up and down the length of the Great Plains as we progress into Thursday and Friday, but not so much so that it is able to hold off any potential advancing troughs, as we will see by the weekend. That being said, it will serve to prolong our dry period through the week and introduce another round of well-above average afternoon temperatures. Wednesday will still be fairly mild, with highs in the 70s areawide, while the ridge is still getting its act together, but by Thursday the sweltering conditions return in force, with lower 80s across the majority of the ArkLaTex. Friday will be warmer still, with upper 80s encroaching as far north as the I-20 corridor. Bear in mind that this is based on NBM model output, which has a known tendency to weigh climatological data heavily, so depending on the amplitude which the culprit ridge achieves, some sites climbing into the lower 90s is within the realm of possibility. For the moment, however, continuing to run with the NBM guidance, but will watch temperature trends under the ridge closely as the week continues. The dry period which will have defined much of the week will begin to come to an end Thursday, when a weak shortwave will push east over the Plains. This shortwave may clip our northern zones just enough to bring a slight chance of showers and storms to McCurtain county and portions of southwest Arkansas starting Thursday afternoon and lasting potentially into Friday morning. The next true weathermaker will organize itself as the work week concludes. An upper level trough will dig south from the upper Plains as it ejects eastward from the Rockies. However, model discrepancies remain quite pronounced regarding the amplitude of the trough, how far south it will dig, whether or not it will form a closed upper level low, whether or not it will achieve a negative tilt, and so forth. What can be said with reasonable certainty is that the majority of the Four State Region will be in for another round of rainfall starting as soon as Saturday morning, with new guidance favoring increasing PoPs, particularly through the late afternoon and early evening hours. Higher end rainfall chances remain with us through early Sunday and PoPs do not depart entirely as Monday begins, suggesting either the lingering effects of the longwave trough or a somewhat potent shortwave developing in its wake. Either way, the ArkLaTex will not be entirely dry as the long term period concludes, especially across our northern zones. Despite the high confidence in rainfall, current guidance keeps this week`s warm trend around for the remainder of the long term, with upper 80s for much of the region through the weekend and into early next week. As for the seasonal question on everyone`s minds when such a setup presents itself, the bottom line up front is that as of the latest severe weather outlooks, predictability remains too low throughout the long term period across the ArkLaTex. However, a 15% region exists across much of Oklahoma and north central Texas for Day 5 (Friday) and just barely misses us to the west, and this region in particular will bear watching as the week continues. It being late April, and with the aforementioned spread amongst constituent long term models, severe weather development cannot yet be ruled out entirely. Stay tuned for forecast updates as the week continues. && .PRELIMINARY POINT TEMPS/POPS... SHV 56 75 49 76 / 10 10 0 0 MLU 56 72 47 74 / 30 10 0 0 DEQ 47 73 46 74 / 10 0 0 0 TXK 52 72 47 74 / 10 0 0 0 ELD 51 71 43 74 / 10 0 0 0 TYR 54 74 50 76 / 10 0 0 0 GGG 54 74 48 76 / 10 10 0 0 LFK 57 76 50 79 / 30 20 0 0 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...None. LA...None. OK...None. TX...None. && $$ 09/33