Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/16/22

National Weather Service Albany NY
1028 PM EDT Tue Mar 15 2022 .SYNOPSIS... A cold front will move southward overnight with the light rain and mountain snow ending and some patchy fog developing. Mainly dry and mild conditions are expected late tonight through Wednesday night. A storm system tracking towards the mid Atlantic coast on Thursday may brush parts of our area with some rain showers. Temperatures will remain above normal through the rest of the work week. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... UPDATE as of 1028 PM EDT...A weak disturbance moving along a cold front is moving across southern New England bringing spotty light rain and snow across the forecast area as a cold front moves southward. The boundary is still north of the mid Hudson Valley, southeast Catskills and NW CT and the I-84 corridor. Some light wet snow has fallen across the southern Adirondacks, where temps have fallen to 32F in the NYS Mesonet. Spotty light rain has fallen across southern VT and the I-90 corridor south and east with a few hundredths to a tenth of an inch. Based on the observations and 3-km HRRR and NAM, the pcpn should diminish between midnight and 2 am from west to east. Any snow accumulations will be a coating to less than an inch in the mountains. Cold advection will occur in the wake of the front causing temps to fall into the 30s to lower/mid 40s. Patchy fog may develop mainly in valleys or sheltered locations with residual low level moisture in place and little wind overnight in these areas. Expect low stratus clouds to persist in the early morning hours, especially over the higher terrain. Lows tonight will range from the upper 20s to lower 30s in the mountains to mid and upper 30s in the valleys. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/... On Wednesday, a surface anticyclone will become established off the New England coast with a mild southerly flow developing across our area. Heights will be rising aloft, resulting in mild temperatures and no precipitation. Low stratus clouds and/or fog in the morning should dissipate by afternoon, with mostly sunny skies expected. Temperatures should warm into the 50s for most of the area, with highs averaging around 10 degrees above normal for mid March. Continued dry and mild weather in store for Wednesday night, with a persistent/light southerly flow across the region with high pressure centered well east of New England. There could be some low stratus clouds and/or patchy fog developing, especially across the southern half of the area closer to the marine influence. Thursday should be mainly dry for at least the northwest half of the area. We will have to monitor a cyclone tracking northeastward from the eastern Carolinas off the mid Atlantic coast during the day. Most sources of model guidance keep this cyclone far enough away for only glancing effects in our area. A few rain showers cannot be ruled out along the northwest periphery of this system, so will mention of chance PoPs from around the Saratoga and Capital Region south and east. Any shower activity looks to be light and mainly scattered. This system should at least spread a canopy of cloud cover that will affect most of the region. The clouds should keep temperatures down somewhat, but it will still be mild by mid-March standards(highs mainly in the 50s). As the cyclone continues to track northeast (south of Cape Cod) Thursday night, a few showers may linger into the evening for areas mainly from Albany south/east. Otherwise, dry conditions are expected for the rest of the night as a ridge of high pressure builds in from the west. Mild temperatures will persist, with lows mainly in the upper 30s to lower 40s. && .LONG TERM /FRIDAY THROUGH TUESDAY/... A complex low pressure system will bring some wet and unsettled weather into eastern NY and western New England late Fri night and for the upcoming weekend. Drier weather will return next week with a high amplitude ridge building in over the Northeast. Fri-Fri Night...A mid and upper level ridge weakens over the Northeast on Friday, and the mid/upper flow becomes southwesterly aloft ahead of a low pressure system moving into the Midwest early Fri night. In the warm advection, ahead of the low expect temps to rise above normal in the lower to mid 60s with some upper 60s in the mid Hudson Valley, and 50s over the higher terrain. Mid and high clouds will be increasing but the daytime period should be dry. The cyclone moves toward the lower Great Lakes Region with the warm front bringing some showers from southwest to northeast across the forecast area. Some wet bulb cooling may change the pcpn over to some wet snow over the southern Adirondacks. Any accumulation is expected to be light. Periods of rain will be widespread towards daybreak. Lows will be in the mid 30s to lower 40s north of the Mohawk Valley and Capital Region with mainly lower to mid/upper 40s south and east. Sat-Sat Night...The parent cyclone moves slowly over the central and northern Great Lakes Region based on the 12Z GFS/ECMWF/Ensembles. A secondary low may form near southern and eastern New England. It is possible a dry slot moves in during the afternoon. Overall, strong moisture advection ahead of an occluded boundary will continue periods of rain at least into the afternoon. PoPs were kept in the likely and categorical range. In the damp conditions, max temps will only be in the 40s to lower 50s over the mtns, and lower to mid 50s in the valleys. The occluded front will move across the region, and the mid and upper level trough will linger. A mixture of rain and snow showers is possible with the better chance of snow showers over the southern Adirondacks, the southern Greens and possibly into the western Mohawk Valley, and the northern Catskills. Some light wet snow accumulations of a coating to an inch or two are possible. Lows will be in the upper 20s to mid 30s over the mtns, and mid 30s to lower 40s in the valley. Sun-Sun Night...The medium range guidance and ensembles continue to show cyclonic flow persisting aloft with the mid and upper level trough lingering over the upstate and New England. The cyclonic vorticty advection tied to the diurnal heating will trigger isolated to scattered showers north of the mid Hudson Valley and NW CT with some snow showers mixing in over the southern Adirondacks. Highs will be in the mid 40s to lower 50s in the valleys, and mid 30s to mid 40s over the hills and mountains. The upper level trough gradually moves down stream Sunday night. Some lingering snow showers and flurries will continue over the southern Dacks and southern Greens. Colder air infiltrates the region with lows in the mid 20s to lower 30s over the higher terrain and lower to mid 30s in the valleys. Monday-Tuesday...A trend to drier weather is expected on Monday with the trough axis down stream and mid and upper level ridging building in. Temps look seasonable for late March with 40s and 50s for highs. Some radiational cooling is possible Monday night with the sfc high building in with mostly clear skies and light winds, as lows will be in the 20s to mid 30s. Mid and upper level heights increase with ridging over the East Coast for Tuesday. Max temps will run above normal with 40s to lower 50s over the higher terrain and lower to mid/upper 50s in the valleys. && .AVIATION /03Z WEDNESDAY THROUGH SUNDAY/... A cold front will continue settling southward this evening, as a weak wave of low pressure tracks along the front. Weak high pressure will then build across the TAF sites during Wednesday. Light rain will gradually overspread the TAF sites this evening, and should last through around 06Z/Wed. The rain should be light, so expect mainly VFR conditions initially, however a period of MVFR Cigs/Vsbys will be possible between roughly 03Z-06Z/Wed as the lower levels of the atmosphere moisten. There could be a bit of wet snow mixing in briefly at KGFL. After the precipitation ends, lingering low level moisture will allow for patchy fog and low stratus to be in place after 06Z/Mon. It`s unclear exactly how low visibility or ceilings will be, but for now, will go with IFR Vsbys and MVFR Cigs around 1-2 kft. There could be periods of LIFR/VLIFR conditions between 08Z-12Z/Wed, but it`s unclear at this time and may depend on just how much rainfall occurs. Low clouds and possible fog may linger as late as 13Z-15Z/Wed, before clearing develops and VFR conditions return. VFR conditions are then expected for Wednesday afternoon, with just some occasional high clouds, and a few cumulus clouds between 4000-6000 FT AGL. Winds will become north to northeast at 4-8 KT this evening (although will initially be from the southwest at KPOU until around 01Z/Wed), becoming light/variable after midnight through Wednesday morning. Winds will then become south to southwest at 4-8 KT by Wednesday afternoon. Outlook... Wednesday Night: No Operational Impact. NO SIG WX. Thursday: Moderate Operational Impact. Chance of SHRA. Thursday Night: Low Operational Impact. Slight Chance of SHRA. Friday: No Operational Impact. NO SIG WX. Friday Night: High Operational Impact. Likely SHRA...RA. Saturday: High Operational Impact. Definite SHRA...RA. Saturday Night: Moderate Operational Impact. Chance of SHRA. Sunday: Low Operational Impact. Breezy. Slight Chance of SHRA. && .FIRE WEATHER... An upper level disturbance along a southward moving front will continue to bring rain and mountain snow showers into this evening. Mainly dry and mild conditions are expected late tonight through Wednesday night. A storm system tracking towards the mid Atlantic coast on Thursday may brush parts of our area with some rain showers. Temperatures will remain above normal through the rest of the work week. Relative humidity values in increase to around 100 percent tonight, dropping to minimum values of between 45 and 55 percent on Wednesday. RH will increase to around 85 to 100 percent Wednesday night. Winds tonight will become northwest around 5 mph, shifting to the southwest around 5 mph on Wednesday. Winds on Wednesday night will be southerly around 5 to 10 mph. && .HYDROLOGY... No hydrologic issues are anticipated through at least the several days. Temperatures will continue to moderate this week, with well above normal readings expected by Thursday into Friday. Precipitation associated with a front moving southward across the area through tonight will only bring light QPF to the area. Otherwise mainly dry weather will occur through Friday, with just some scattered light showers on Thursday. The warmer temperatures will result in snowmelt across the higher terrain where there is still 1 to 5 inches of liquid equivalent in the snowpack. The snowmelt should follow diurnal trends, as nighttime temperatures will drop into mainly the 20s/30s in higher terrain areas. River rises are expected, but should not be enough to cause flooding. MMEFS forecasts indicate no river points exceeding minor flood stage through the next 7 days. For details on specific area rivers and lakes, including observed and forecast river stages and lake elevations, please visit the Advanced Hydrologic Prediction Service /AHPS/ graphs on our website. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. MA...None. VT...None. && $$ SYNOPSIS...JPV/Wasula NEAR TERM...JPV/Wasula SHORT TERM...JPV LONG TERM...Wasula AVIATION...Frugis/KL FIRE WEATHER...JPV HYDROLOGY...JPV
Area Forecast Discussion
National Weather Service Boston/Norton MA
1013 PM EDT Tue Mar 15 2022 .SYNOPSIS... Round of brief showers this evening, especially along and north of the Mass Pike. Drier weather expected Wednesday. Above normal temperatures continue on Thursday with some showers likely sometime later in the day into the evening. Even warmer on Friday and with plenty of sunshine many locations away from the immediate coast/localized sea breeze potential will probably see high temps of 70+. Cooler temps arrive this weekend along with some rain for Saturday. Mainly dry weather with more seasonable temperatures are expected early next week. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... No major changes to the forecast this evening. Latest runs of the HRRR ensemble and National Blend or models appeared to have a good handle on the timing of the showers across southern New England. Made some tweaks to rainfall chances and timing overnight. Still expecting the majority of showers to be offshore early Wednesday morning. Previous Discussion... A fast moving shortwave crosses the region this evening. The bulk of the forcing/dynamics will be across the northern half of our region. Therefore, most of the showers will impact northern MA but a few brief showers may find their way further south. Even in northern MA though this activity will be short-lived and exit the region near or shortly after midnight. Low temps overnight will be in the 30s to near 40. We may have to watch for a bit of patchy fog toward daybreak, where there is some partial clearing. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/... High pressure once again builds in on Wednesday bringing subsidence, clearing skies, and dry weather. Additionally, anomalously warm temperatures continue to surge north, and with mixing to near 900 mb on Wednesday we`ll once again see highs in the upper 50s and some low 60s. Initially more west/downslope winds may help the CT River valley overperform compared to elsewhere. The ridge of high pressure lingers overnight keeping things dry, though clouds will be on the increase. Lows will once again be in the upper 30s. && .LONG TERM /THURSDAY THROUGH TUESDAY/... Highlights... * A period of wet weather likely late Thu into Thu evening with relatively mild temperatures persisting * Dry & unseasonably mild on Fri with highs of 70+ likely in many locations away from the immediate coast/localized sea breezes * Cooler afternoon temperatures this weekend with rain on Saturday * More seasonable temps early next week with mainly dry weather Details... Thursday and Friday... The Ensembles continue to be in very good agreement in the overall pattern. Deep closed low in the vicinity of Alaska will team up with the lack of upper level blocking in the North Atlantic. This translates to a +EPO/+NAO, which supports zonal flow and will keep the cold air locked up well to our north. The result will be unseasonably mild temps Thu and well above normal temperatures on Fri. High temperatures on Thu will be in the middle 50s to the lower 60s, despite the likelihood of some showers especially across eastern MA/RI later in the day and into the evening. The mildest of those readings may end up in our northern zones; given the greater risk of steadier rain will be near and especially southeast of the I-95 corridor. There still remains considerable disagreement with the track of a shortwave and associated surface low on Thu. The NAM/RGEM have a track closer to the coast and indicate a steady rainfall late Thu into Thu evening. Meanwhile...the global models indicate a track further southeast with just a brief period of light showers. Still a significant spread amongst the GEFS/EPS members on the track. Appears that the model guidance may be struggling as a result of limited baroclinicity considering the time of year. Still need a bit more time to sort this out, but it does appear that at least some light showers are in store for much of the region later Thu into Thu evening. Friday will be the mildest day of the week with well above normal temperatures. Guidance has 850T of +6C along with westerly flow and expected sunshine. MOS guidance is likely too cool given a well mixed atmosphere in pre-greenup, at least away from portions of the immediate coastal/localized sea breeze potential. Therefore, many locations should see high temps of 70+ away from parts of the immediate coast. This Weekend... Low pressure will be approaching the region from the southwest late Friday night into Saturday. Pretty good agreement in the guidance that we will see rain on Saturday. Given high pressure in the Canadian Maritimes, easterly flow may keep highs in the 40s to lower 50s and on the chillier side of those readings if the low cuts underneath us. There probably will be some improvement by Sunday, but lingering upper trough and shortwave energy may keep a lot of clouds and even a few lingering showers across our region. High temps probably in the 40s to middle 50s depending on how things transpire, but leaning towards the cooler readings. Early Next Week... Appears lingering upper trough and high pressure slowly building in from Quebec will result in more seasonable temperatures by early next week along with mainly dry weather. && .AVIATION /02Z WEDNESDAY THROUGH SUNDAY/... Low - less than 30 percent. Medium - 30 to 60 percent. High - greater than 60 percent. Tonight...Moderate confidence. VFR conditions deteriorate to MVFR-IFR late this evening into the overnight hours, mainly across northern and eastern sections of the region. A brief round of showers this evening is also expected, mainly across northern MA, but a few will find their way south. Patches of fog are also possible late. Light NW winds. Wednesday...High confidence. MVFR-IFR conditions in northern and eastern sections of the region will gradually improve to mainly VFR by late morning/early afternoon. Light S winds with sea breezes along the coast. Wednesday night...High confidence. VFR. Light southerly winds. KBOS TAF...High Confidence in TAF. KBDL TAF...High Confidence in TAF. Outlook /Thursday through Sunday/... Thursday: Mainly MVFR, with areas VFR possible. Breezy. Chance RA. Thursday Night: MVFR/IFR conditions possible. Breezy. Chance RA. Friday: VFR. Breezy. Friday Night: Mainly MVFR, with local IFR possible. RA likely. Saturday: Mainly MVFR, with areas IFR possible. Windy with local gusts up to 30 kt. RA. Saturday Night: Mainly MVFR, with local IFR possible. Breezy. Chance RA. Sunday: Mainly VFR, with areas MVFR possible. Breezy. && .MARINE... Forecaster Confidence Levels. Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. A weak low pressure and front will cross the waters tonight, followed by high pressure Wednesday. Relatively light winds and seas expected most of this time through Wednesday night. Outlook /Thursday through Sunday/... Thursday: Winds less than 25 kt. Seas locally approaching 5 ft. Rain likely. Thursday Night: Winds less than 25 kt. Areas of seas approaching 5 ft. Rain likely. Friday: Winds less than 25 kt. Seas up to 5 ft. Friday Night: Winds less than 25 kt. Seas up to 5 ft. Chance of rain. Saturday: Moderate risk for Small Craft Advisory winds with local gusts up to 30 kt. Areas of rough seas. Chance of rain. Saturday Night: Moderate risk for Small Craft Advisory winds with gusts up to 30 kt. Rough seas up to 8 ft. Chance of rain. Sunday: Moderate risk for Small Craft Advisory winds with gusts up to 25 kt. Rough seas up to 8 ft. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...None. MA...None. RI...None. MARINE...None. && $$ SYNOPSIS...Frank/BW NEAR TERM...Belk/Frank SHORT TERM...BW LONG TERM...Frank AVIATION...Belk/Frank/BW MARINE...Frank/BW
Area Forecast Discussion
National Weather Service Charleston SC
1041 PM EDT Tue Mar 15 2022 .SYNOPSIS... An area of low pressure will track through the region through Wednesday night. Another cold front will slip through the region later Friday into Saturday, with high pressure returning early next week. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... The back edge of the rains associated with a mid level impulse and the greatest surface mixing ratios will pull offshore by 12-1 AM, leaving us with NVA for a few hours. Guidance provides mixed signals on the evolution of the next batch of convection associated with the approach of a closed low aloft, it`s counterpart at the surface, both of which shift east along the northern Gulf Coast region, and a warm front to the south. However, with increasing isentropic ascent and better forcing from these aforementioned features, we anticipate a climb in convective coverage after about 3 am. Activity looks to be highest near and west of I-95, which aligns with the HRRR and NAMNest which have performed the best the past several hours. The places look to have the best overlap of upper difluence with a 80-90 kt 250 mb jet, upward omega and a 30-40 kt jet at 925 mb. There is some negative Showalter values arriving over parts of Georgia before daybreak, so we did show mention of a slight chance of t-storms. No major changes to temps. Previous discussion... An impressive southern stream closed low across the lower Mississippi Valley will trek east through the night, resulting in a slow downward trend to heights aloft. An associated surface low initially near New Orleans will head toward the Florida Panhandle and into southern Alabama overnight, while a warm front extends east-southeast, linking up with a developing low off the northeast Florida coast. That secondary low occurs in response to a short wave embedded within the southwest flow aloft. Moisture will continue to deepen out of the Gulf and the Atlantic, as PWat reaches near 1.5 inches. That along with difluence aloft and isentropic ascent increasing on various surfaces will lead to showery weather across the area. Models differ regarding where the highest chances will be found, but based on recent trends we do have our greatest coverage in Georgia early on, with PoP as much as 70-90% in some locations. We suspect additional revisions through the night. There does remain the potential for some elevated t-storms late across Georgia, with Showalter Indices below zero. And that has been maintained from the previous forecast. It`ll be a mild night with temps far above climo given extensive thick cloud cover and an east and southeast synoptic flow. In fact many places might not even be able to drop below 60F. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/... High Impact Weather Potential...watching for stronger storm possibilities on Wednesday. Pattern Synopsis/Forecast: A fairly progressive flow pattern remains in place across the CONUS today with a pronounced upper low moving into the western Gulf Coast region. This system will bring our next stretch of active weather to the region for midweek. Another Pacific short-wave trough is advancing into the west coast and will undergo some amplification across the central CONUS toward the end of the week, before advancing up through the Great Lakes this weekend. Larger scale flow will then become a bit more amplified across the CONUS late in the weekend into next week as one more Pacific short- wave trough works it`s way into the CONUS. Details: Closed upper low will advance into the Gulf Coast states by Wednesday morning before lifting up through northern Georgia and the western Carolinas Wednesday afternoon and Wednesday night. At the surface, low pressure is expected to develop along the central Gulf Coast overnight into Wednesday, then slip up through the eastern Carolinas through Wednesday night. Associated surface warm front will be sliding northward through the area overnight through Wednesday which will place at least a portion of the forecast into the warm sector. Still some mixed signals in guidance regarding the overall precip evolution late tonight into Wednesday with the advancing warm front, with some guidance suggesting a bit of a one area of precip moves up through the central/western Carolinas and second piece along the main moisture channel getting shunted off to our S/E (sort of seeing that pattern trying to emerge on regional radar plot). Regardless, as we get later into the morning and particularly the afternoon, increasing QG-forcing for ascent and upper level height falls with the upper low will be spreading into the region and likely to bring one or more additional rounds of showers and thunderstorms, persisting into the evening. Categorical pops remain justified through the day Wednesday, although the exact timing of the more widespread precip remains problematic (as usual) and will likely need adjustments. Thunderstorm potential: Plume of elevated MUCAPE will be advecting up into the region overnight and into the day Wednesday, and there may be some ongoing, elevated thunderstorms in the region to start the morning. But as we get later in morning and afternoon, heating will likely generate some surface based MLCAPE, dependent upon the track of the low and attending boundary and, of course cloud cover and how much heating we can attain. Right now, the better instability is likely to be across the GA counties where around 1K J/Kg of MLCAPE is possible per HREF/GFS solutions. Meanwhile, axis of stronger southwesterly unidirectional low-mid level flow along the eastern side of the low will be spreading into the region, resulting in 40 to 50 knots of 0-6Km bulk shear for the afternoon. This continues to suggest at least some potential for stronger storms and possibilities of a few severe storms if all aligns. The entire forecast area remains outlined in a marginal risk for severe storms in SPC`s Day2 outlook, which is reasonable at this juncture. Later in the week: Low amplitude short-wave ridging, weak-ish surface high pressure and drier air build through the SE states for Thursday and going into Friday. There may be some fog around Thursday morning, although we do not have that explicitly mentioned in the forecast as of yet. But a return of FAIR weather is anticipated for Thursday and into the day Friday, before some low end shower potential creeps back into the forecast later in the day Friday (see below). && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... Pacific short-wave trough will dip into the central/southern plains by early Friday before lifting into the Great Lakes heading into the weekend. This will gin-up another storm system in the southern Plains that also tracks into the Great Lakes, driving a boundary through the SE states later Friday through Saturday. Primary forcing with this system will slide by to our north. But enough low level convergence with the boundary...upper level support and moisture transport ahead of the front to maintain our higher end chance pops, Friday afternoon into Saturday. Dry weather returns Sunday and the first half of next week. Warmest day this week is looking to be Friday, ahead of the approaching cold front. Daytime temps dip back off for the weekend, but still around of just above seasonable norms. Warming again next week. && .AVIATION /02Z WEDNESDAY THROUGH SUNDAY/... VFR a good chunk of the night. But then for later tonight and early Wednesday we anticipate ceilings lowering as dew points climb in advance of a warm front, and low pressure treks along the northern Gulf coast and a secondary low forms off the northeast Florida coast. MVFR seems most likely, but IFR can`t be ruled out, especially at KSAV. Showers will become more steady Wednesday as the surface low and associated warm front draw closer, in tandem with forcing from a closed low approaching from the west. Low end MVFR ceilings are forecast, with a chance for IFR, at least at times through the day. At least some surface based instability settles into the local area, tempered though by the low cloud cover. Because of this we chose not to go anything more than VCTS at KCHS, KJZI and KSAV Wednesday, but refinements could be required as the event gets closer, and tempo groups could be required for TSRA. This seems most likely at KSAV from about 12-20Z at KSAV and a few hours later at KCHS and KJZI. Extended Aviation Outlook: High confidence for MVFR ceilings impacting the terminal sites Wednesday night/early Thursday, along with a risk for periodic IFR flight restrictions during that time. Conditions trend back to VFR on Thursday and remain in place into Friday, although late night/morning fog is possible early Friday morning. Additional flight restrictions anticipated again Friday night into Saturday with another cold front that will pass through the region. && .MARINE... There has been a tightening of the gradient between the Atlantic high and the upstream low across southern Mississippi and southern Alabama. As a result we have bumped winds up a bit from the previous forecast. Because of these higher speeds we began the Small Craft Advisory on the AMZ374 waters a little quicker than before; now starting it at 5 AM as some 6 footers arrive by that time. There does remain a chance for the Small Craft Advisory in Charleston Harbor from about 15-21Z Wednesday. But it still looks too marginal that I`d prefer to let the next shift take another look when more guidance becomes available. Previous discussion... Tonight: High pressure centered north of Bermuda will give way to a warm front from the south, while a very subtle inverted trough persists over the shelf waters. This trough isn`t as pronounced as many of these types are, so it is not expected to keep winds NE over the shelf waters, instead it`ll just be Easterly through the night. Speeds of 10 or 15 kt early on will increase to 15 or 20 kt by daybreak Wednesday. With the favorable onshore fetch, seas will reach 3-5 ft, highest on the outer Georgia waters. We did consider raising a Small Craft Advisory for Charleston Harbor for Wednesday, but since it is so marginal, we choose to hold off at this time. Extended Marine Outlook: Low pressure system will impact the region Wednesday and Wednesday night. Low end Small Craft Advisory conditions are expected in the Charleston nearshore waters Wednesday/Wednesday evening, and in the Savannah outer waters on Wednesday. There will be a low risk of SCA conditions late in the week into Saturday depending on the strength of another cold front that will be moving through the region. Rip Currents: Strong onshore winds, swell waves, and astronomical influences will yield a Moderate Risk of rip currents at Lowcountry/Coastal Empire beaches on Wednesday. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...Small Craft Advisory from 5 AM to 7 PM EDT Wednesday for AMZ374. Small Craft Advisory from 7 AM Wednesday to 1 AM EDT Thursday for AMZ350. && $$ NEAR TERM... SHORT TERM...TBA LONG TERM...TBA AVIATION...TBA MARINE...TBA
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
955 PM EDT Tue Mar 15 2022 .SYNOPSIS... A moist low pressure system crosses the Gulf states tonight and Wednesday reaching the South Carolina coast Wednesday evening. Widespread rain will cross the area then taper off and end Wednesday night. Dry weather returns Thursday with a weak, yet moist, cold front crossing the region late Friday into Saturday. High pressure will provide dry weather from Sunday into the first part of the upcoming week. && .NEAR TERM /THROUGH WEDNESDAY/... As of 945 PM EDT Tuesday: Forecast still on track. A few modifications were made to the PoPs in an attempt to capture the slow and steady encroachment of drizzle along the southwest tier of the CWA. A bowling ball of a closed, stacked low pressure system will rotate through the deep south, pushing into GA late in the day Wednesday. Moisture influx ahead of the system and favorable upper level diffluence will support continued lowering and thickening of clouds this evening followed by slow but steady increase in rain chances later this evening into Wednesday. Peak of rainfall coverage and rates will be Wednesday with a stout 30 to 40 mph low level jet, divergence aloft and steepening upper level lapse rates thanks to the approaching of the cold upper low possibly supporting rainfall rates in excess of a half inch per hour. Fortunately the system and associated heavier cells should generally maintain forward momentum, limiting rainfall amounts and the threat for excessive rainfall. As it stands, much of the area from the escarpment and points east has a good shot at an inch plus of rainfall with localized amounts of two plus inches. While a hybrid wedge will likely limit surface based instability with the system Wednesday, elevated instability rising up and over the wedge front across the southern tier and impressive mid level lapse rates may support a few stronger thunderstorms south of I-85 with large hail and damaging wind the primary threats. Rainfall tonight will help to lock in the expected hybrid wedge which when combined with the widespread rain and cloud will make for a dreary Wednesday with daytime highs topping off in the 50s to near 60. && .SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/... As of 100 PM Tue: Upper low will continue to wobble northeast across the CWA Wednesday night. Most of the CWA will remain under a shallow sfc high and in-situ CAD, but temps should remain mild enough to maintain an all-liquid forecast. Elevated convection appears possible above the wedge inversion; TMB looks likely to be near our southeastern border and any SBCAPE thus should be kept south of the CWA. That said, NAMNest depicts small pockets thereof within our border counties overnight. Regarding tornado threat, shear parameters are not all that exciting although perhaps too strong for comfort; hodographs are chaotic except in the lowest kilometer, and it is hard to find a prog sounding where a parcel could be lifted from below 1 km. Decent lapse rates above the inversion however will combine with modest effective shear to pose some hail risk into early Thursday. HRRR and HiRes-FV3 generate some short updraft helicity swaths, seemingly from elevated parcels. SPC Day 2 brings Marginal Risk into our far south with 5% hail prob; based on these findings those probs could end up being brought a little further north into the area if anything. Flash flood threat early Thursday appears limited but nonzero. The plume of moisture preceding the upper low may have exited the CWA prior to the start of the period, but storm motion and Corfidi vectors will shrink as the low moves overhead. As noted above effective hodographs do not reveal much organization, but at least a small possibility exists for training convection. Most guidance agrees the upper low will be in an unfavorable position to produce precip or convection in our CWA by mid-morning Thursday, and CAM output backs that up. The ECMWF is a bit slower than the consensus in carrying it out of the area, but overall we allow PoP to diminish during the morning. Sfc/upper ridge should fill in from the west in the wake of the low, keeping us dry and with above-normal temps through Friday morning. && .LONG TERM /FRIDAY THROUGH TUESDAY/... As of 145 PM Tue: A mature low pressure system will move thru the mid-Mississippi Valley on Friday, while the warm conveyor belt of that system crosses the southern Appalachian region. Deep saturation should occur over the CWA, along with a wave of strong midlevel WAA, and accordingly PoPs return. Given modest upper level lapse rates, the setup may support another round of elevated convection Friday into Friday night. A narrow warm sector may reach the CWA Friday night between the WCB and cold front; a plume of small SBCAPE is seen on the global deterministic models, concurrent with large deep layer shear. Warm midlevels appear to be a limiting factor for the viability of any sfc based parcels, but for now this appears to be a period of interest. Cold front should clear out PoPs and sky cover for Saturday. Winds do turn northwest along the southern Appalachians, but GFS and Canadian GDPS depict too little low-level moisture for continuing PoPs. ECMWF is the only available model depicting NW flow precip later Saturday, but it continues to show it into early Sunday. Temps should fall back to about climo Saturday night, but still warm enough that if precip were falling at that time in the NW flow areas, it would be more likely rain than snow. Dry weather should last the remainder of the fcst period, with temps above normal beneath a sfc high of southern Rockies origin. && .AVIATION /02Z WEDNESDAY THROUGH SUNDAY/... At KCLT and elsewhere: All sites are presently VFR as a cirrus shield encroaches on the region out of the southwest. Most areas are CLR or only carrying FEW/SCT cirrus decks, but as these thicken in the next few hours, a gradual transition to BKN/OVC is expected. A midlevel (still VFR) cloud deck is expected to push in thereafter. Deterioration should come as a slow burn, with sites generally expected to transition to MVFR ceilings from west to east between 08Z and 12Z, except for KCLT, which may see a marked delay in the arrival of lower clouds. Winds should remain light and variable the next few hours, before gradually becoming more reliably NEly between 03Z and 06Z. For now, have worked VCSH in starting near or shortly before daybreak; CAMs are generally not handling the onset of rainfall well as aforementioned NE winds result in a hybrid CAD wedge developing overnight. After daybreak, most guidance depicts MVFR visibility developing rather quickly with onset of -SHRA, while lowered (IFR) ceilings only slowly spread eastward across the Piedmont. The Upstate sites as well as KCLT continue to carry PROB30s for -TSRA Wednesday evening - but it remains difficult to pin down an exact timing for convection. Outlook: Brief drying and a return to VFR conditions is expected Thursday and Thursday night. Another moist frontal system and associated restrictions arrives later on Friday. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...None. SC...None. && $$ SYNOPSIS...DEO NEAR TERM...MPR/Munroe SHORT TERM...Wimberley LONG TERM...Wimberley AVIATION...MPR
Area Forecast Discussion
National Weather Service Shreveport LA
934 PM CDT Tue Mar 15 2022 .UPDATE... Still seeing some returns on radar this evening across portions of northern and northeast Louisiana, so will maintain the low end PoPs for this area as we move into the overnight hours before they end completely overnight. The inherited forecast appears to be on track, so not many changes needed other than to account for current trends, which was not far off from the forecast. Look for patchy fog to develop overnight with lows in the lower to mid 40s across the region. /33/ && .PREV DISCUSSION... /issued 630 PM CDT Tue Mar 15 2022/ AVIATION... For the 16/00z TAFs...Still seeing a wide variety of flight conditions late this afternoon across the region, however, VFR conditions are starting to become more dominant. KMLU continues to report IFR conditions with low cigs and -RA, KELD continues to report MVFR conditions with lower cigs, while the remainder of our sites are now reporting VFR conditions. The upper-level low continues to move towards the east this afternoon, and radar returns have been trending in the downward direction. Should see some fog develop overnight across much of the region, which will bring some LIFR flight conditions overnight and towards Wednesday morning before scattering out by late Wednesday morning. /33/ PREV DISCUSSION... /issued 218 PM CDT Tue Mar 15 2022/ SHORT TERM.../Tonight through Wednesday Night/ Watervapor, Visible Satellite Imagery and radar mosaic continues to show our upper level trough spinning across the heart of the Four State Region and since the noon hour, we have seen an increase in light rain coverage across portions of NE TX into NW LA and SC AR. Given the location of the upper trough and the slow eastward progression expected overnight, have held onto high chance pops beginning at 00z across our eastern third with slight chance pops as far west as the Piney Woods of NE TX with pops ending across our far eastern zones by 06z. Cloud cover has been pesky today, in and out across our far western and southern fringes but feel like this cloud cover will hang in through much of the evening elsewhere, albeit thinning across our northwest half after midnight. It`s this thinning that is concerning because that will likely lead to fog development late tonight. HRRR and latest 3KM NAM output is pretty insistent that dense fog will develop across our west and northwest half overnight. For the forecast, have mentioned patchy fog everywhere tonight after midnight and introduced patchy dense fog across our western half which is just shy of what we would need for a dense fog advisory. Will let the next shift take a crack at this possibility if they think one is necessary. Assuming this forecast holds, we will keep the dense fog in through much of the morning across at least our western zones with improving conditions during the afternoon. Other than these short term concerns over the next 24 hours, the remainder of the forecast is pretty much a temperature one with high on Wednesday warming in the lower to middle 70s assuming we break the cloud cover on Wednesday with overnight lows Wednesday Night falling into the middle 40s to lower 50s. 13 LONG TERM.../Thursday through Tuesday Night/ As we move into the end of the work week, the SPC has a marginal risk for much of our area on their day 3 valid through Friday morning. Our next cold front will be arriving with another vigorous mid level trough during the overnight hours. Overall, this system is looking fairly strong like the one last night, but just with limited moisture return. So our QPF on the WPC day 3 is only anywhere from a tenth to half inch. So this will help to keep us drying out so much before the next arrival early next week. This will be good for continued progress on the drought of late. The GFS and ECMWF are very similar with an open wave centered over Oklahoma by sunset on Thursday. The upper trough does sit back and tilt slightly negative a tiny bit before ejecting out east of the MS River valley by early on Friday. Most of the QPF is baked into the nighttime hours with signal lighting up right around 00Z and ending by 12Z. A large area of surface high pressure at 1025mb will sprawl in under the departing upper low and make for notably cooler readings for Friday afternoon and on into the weekend especially on the low end with more seasonal upper 30s and lower 40s. Highs will be a little closer to normal on Saturday and even back above for Sunday. The southerly flow returns early next week as the surface high moves east, with our morning lows jumping back through the 50s and into the 60s toward the end of this long term. Our highs early next week are looking to be well above normal and loaded with Gulf moisture for another potent upper trough arriving Monday night. The GFS is a little farther north on a closed low of 544dam with ECMWF not nearly as deep, but much farther south over the TX panhandle by Monday evening and both with the QPF starting to ramp up for us once again during the overnight. Much will linger into Tuesday as the whole system takes it`s time with a big ridge over the Atlantic seaboard. More rain we will take, but timing could be bumpy late on Monday for I-30 and then down our I-20 corridor during Tuesday. /24/ PREV DISCUSSION... /issued 1153 AM CDT Tue Mar 15 2022/ && .PRELIMINARY POINT TEMPS/POPS... SHV 47 73 49 78 / 30 0 0 10 MLU 50 71 48 75 / 50 0 0 0 DEQ 41 74 45 76 / 20 0 0 10 TXK 47 72 50 76 / 20 0 0 10 ELD 46 73 47 76 / 50 0 0 0 TYR 46 74 50 76 / 20 0 0 20 GGG 46 74 49 77 / 20 0 0 10 LFK 47 75 49 78 / 10 0 0 20 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...None. LA...None. OK...None. TX...None. && $$ 13/24