Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/13/20

National Weather Service Albany NY
1035 PM EDT Sun Apr 12 2020 .SYNOPSIS... Rain will overspread the region during the early morning, as an intense storm system will impact eastern New York and western New England into Monday night. The storm will bring strong to damaging winds to the area along with moderate to heavy rains and a chance for thunderstorms. In the wake of the system, it will be cooler for the rest of the week with below normal temperature for mid April. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... As of 1030 pm EDT...The clouds continue to thicker and lower ahead of a warm front and the lead short-wave in the deep southwest flow ahead of a potent mid level short-wave trough lifting out of the lower MS River Valley, and the Southeast. A region of upper level diffluence has set up over the Northeast ahead of the potent digging H500 trough depicted on the water vapor imagery. We continued to slow the PoPS down slightly based on current radar returns to the south and the latest 00Z 3-km HRRR trends. We have now gone with a dry forecast prior to 06Z/MON for most of the region. The 00Z KALY soundings is very dry below 700 hPa and it will take a little time to moisten the low-levels. The isentropic lift increases quickly as the potent H925/850 LLJ impacts the region between 06Z-12Z/MON. PoPs were increased to categorical values between 08Z-10Z. The rain will come down moderate to heavy at times by daybreak. Southerly winds will increase to 10 to 20 mph with some gusts in the 25-35+ mph range by sunrise. Lows will be quite mild in the 40s to lower 50s across the region. && .SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/... An intense low pressure system will strong to damaging winds to the area Monday into Monday night along with a moderate to heavy rainfall and chances for thunderstorms. High Wind Warning has been issued for northwestern Connecticut and western Massachusetts for 6 am to 6 pm Monday for southerly winds. Wind Advisory has been issued for Warren and Washington Counties, the Taconics, Mid Hudson Valley and southern Vermont for 6 am and 6 pm Monday for southerly winds. Wind Advisory has been issued for Western Adirondacks, Mohawk Valley, Capital District, Saratoga region, Schoharie Valley, Helderbergs and eastern Catskills for 6 am to 11 pm Monday for southerly winds during the day and westerly winds in the evening. Anomalies continue to be extremely impressive with 850mb/925mb winds +4-6 SD, 850mb moisture flux 6+ SD, PWAT +2-3 SD, 500H/700H -3-4SD and surface pressure -4-5SD. Guidance continues to have a 60 to 90 knots 925mb jet that passes over the NWS OKX and much of the NWS BOX forecast areas during the day morning. Focus for heaviest rain is during the morning hours with the 850mb jet (50 to 80 knots) moving through ahead the system warm front. Have locally heavy rainfall possible in the morning mentioned in the forecast. Focus for thunderstorm threat is during the afternoon in the warm sector. With warm air advection will have inversion in place. An instability will be meager. The Storm Prediction Center has maintained general thunderstorm threat across the northeastern two-thirds of the forecast area and a marginal risk for severe across the southwest third where there is a better chance for some instability to develop. Activity winds down quickly in the evening. Winds will finally back off overnight will remain brisk and gusty across much of the area. With a mild start to the day highs are expected to be in the mid 50s to mid 60s. With the passage of the system cold air advection will cause temperatures to drop around 25 degrees with lows in the 30s to lower 40s with some 20s in the western Adirondacks. Colder and more seasonable Tuesday with a longwave trough across the CONUS with short waves moving through the flow. A weak wave will pas to our well to our south Tuesday and Tuesday night with slight chances for showers grazing the southern most reaches of the forecast area. Colder Tuesday night with lows in the mid 20s to upper 30s. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... The main weather headlines during the extended includes 1) the influence of an amplified mean upper trough that will yield cooler than normal temp anomalies, if not all of the period, 2) multiple weak mid-level disturbances that will bring slight or low chances for some isolated to scattered rain/snow showers to the region Wednesday through Thursday, 3) a stronger impulse that we continue to monitor that has the potential to bring a more widespread threat/chance for precipitation Friday aftn/eve. into Saturday, and 4) the potential for moderating temperatures returning closer to normal levels next weekend. Wednesday through Thursday: Forecast models continue to advertise multiple weak mid-level impulses that will track along the edge of an attendant upper trough overhead. This combined with some diurnal surface heating, lake enhanced and/or orographic (upsloping) effects will help in aiding/triggering some cloud development and thus the potential for scattered rain/snow showers. Given the limited amount of available moisture, significant accumulations of any rain/snow showers are not expected. The higher terrain areas are most favored to see snow showers with light accums of a coating to less than a half inch. Friday through Sunday: Attention then turns to a strong, more vigorous disturbance that will dig into the Pacific Northwest/Northern Rockies midweek before ejecting out of the central U.S. and towards the eastern U.S. late week into the weekend (second half of Friday into Saturday). Forecast models (particularly the GFS and Canadian-NH models) have now come on board with the 00Z ECMWF with this general idea. Given that we`re still 5 days out, it`s still rather early in terms of pinpointing the precise track, location, and intensity of this next storm system. That said, this storm system so far looks to be the most promising and should this storm system track towards our area, it has the potential to bring a greater, more widespread chance for precipitation to the region. Stay tuned for more details as things further get ironed out. Cloud coverage through Saturday will range partly to mostly cloudy. Weak riding will build in late Saturday into Sunday before the next short-wave arrives. Given that the large scale pattern will be highly amplified early in the period before relaxing slightly later in the period, temperatures will start off the period cooler than normal before moderating to near normal levels late in the period. Wednesday through Friday, we will see high temperatures in the 40s to near 50 degrees with some cooler temps in the mid and upper 30s over mtns. On Saturday, high temperatures will be in the 40s to lower 50s and on Sunday well into the 50s and 40s over the mtns. Overnight low temperatures will generally run from the 20s into the lower 30s through the extended. Given that normal high temperatures will run 58-60 degrees during this period, temp anomalies will run 7-9 degrees below average Wednesday through Saturday, and near normal levels on Sunday. && .AVIATION /03Z MONDAY THROUGH FRIDAY/... Clouds will thicken and lower early tonight, and then rain will overspread the region after midnight, as a warm front associated with a strong low pressure moving northeast from the lower and central MS River Valley impacts the area. The low pressure system will track into the central Great Lakes Region, as a cold front will move across the region late tomorrow afternoon into the early evening. Mid level clouds will increase and lower between 03Z-06Z/MON at KGFL/KALB/KPOU/KPSF with an increasing southerly flow ahead of the potent storms system. Initially, light rain will overspread the terminals, but expect the rainfall to increase between 06Z- 10Z/MON, as cigs/vsbys falling into the MVFR and spotty IFR range. The best chance for widespread IFR conditions looks like late Monday morning into the early to mid pm with the cyclone reaching the OH Valley. The rain will become occasionally moderate to heavy, as a strong low-level jet focuses the rainfall. Expect the rain to continue into the pm with a brief warm sector, where cigs may eventually rise back to low MVFR levels, but there is a chance some thunderstorms may break out, and we placed a PROB30 for thunderstorms at all the TAF sites especially between 19Z-23Z/SUN. Conditions may lower to IFR levels in the thunderstorms. Low level wind shear will be dominate starting around 04Z-07Z/ MON from south to north, as the 2 kft AGl winds increase to 40-60 kts. We kept the wind shear going the duration of the TAF cycle at KGFL...removed the groups between 19Z-20Z/MON at KPOU/KALB/KPSF. The strong low-level jet will begin to weaken in the early to mid afternoon, but the cold front will be approaching. The sfc winds will be south to southeast at 7-15 kt overnight with gusts around 20-25 kt developing especially at KALB/KPOU/KPSF between 08Z-12Z/MON. The winds will become south to southwest and increase to 14-24 kt with gusts 25-38 kts in late morning into the afternoon. Outlook... Monday Night: High Operational Impact. Very Windy. Slight Chance of SHRA. Tuesday: Low Operational Impact. Breezy. Tuesday Night: Low Operational Impact. NO SIG WX. Wednesday: Low Operational Impact. Slight Chance of SHRA. Wednesday Night: Low Operational Impact. NO SIG WX. Thursday: Low Operational Impact. Slight Chance of SHRA...SHSN. Thursday Night: Low Operational Impact. NO SIG WX. Friday: Moderate Operational Impact. Chance of SHRA. && .FIRE WEATHER... An intense storm system will impact the region late tonight into Monday night bringing strong to damaging winds to the area along with moderate to heavy rains and chances for thunderstorms. In the wake of the system, it will be cooler for the rest of the week with below normal temperature for mid April. && .HYDROLOGY... A widespread moderate to heavy rainfall will occur late tonight through Monday as an intense low pressure system impacts the region. The Weather Prediction Center has maintained a marginal risk for excessive rainfall for areas to the south and east of the Capital District for Monday. Expecting 1 to 2 inches of rainfall across this area with locally higher amounts across portions of the eastern Catskill. One to 2 inches is also expected across portions of the southern Adirondacks and upper Hudson Valley with up to an inch for the Mohawk and Schoharie Valleys and across the Capital District. Localized higher amounts are possible where thunderstorms occur. Urban and poor draining flooding will be possible. At this time, only Sacandaga River at Hope (Monday evening) and the West Canada at Hinckley (Tuesday) are expected to exceed flood stage otherwise river flooding is not expected. 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...High Wind Warning from 6 AM to 6 PM EDT Monday for CTZ001-013. NY...Wind Advisory from 6 AM to 11 PM EDT Monday for NYZ032-033- 038>041-047>053-058-063-082. Wind Advisory from 6 AM to 6 PM EDT Monday for NYZ042-043-054- 059>061-064>066-083-084. MA...High Wind Warning from 6 AM to 6 PM EDT Monday for MAZ001-025. VT...Wind Advisory from 6 AM to 6 PM EDT Monday for VTZ013>015. && $$ SYNOPSIS...IAA/Wasula NEAR TERM...Wasula SHORT TERM...IAA LONG TERM...Evbuoma/Wasula AVIATION...Wasula FIRE WEATHER...IAA HYDROLOGY...IAA/BGM
Area Forecast Discussion
National Weather Service Bismarck ND
1001 PM CDT Sun Apr 12 2020 .UPDATE... Issued at 937 PM CDT Sun Apr 12 2020 Latest radar imagery shows snow showers from just south of Minot extending southwest to Garrison, Hazen Glen Ullin and Dickinson. Snow showers also extend back west through Watford City, Grassy Butte and Beach. Snow showers are now winding down in Williston. The 00 UTC RAP forecast sounding for Bismarck shows strong omega within the DGZ centered around 07 UTC. 1 UTC RAP analysis also shows a bullseye of very steep lapse rates centered around Killdeer and Dickinson at 03 UTC, and propagating to just west of Bismarck at 07 UTC. then southeast to around Ashley by 10 UTC. This is congruent with a band of low to mid level FG forcing that tracks from New Town to Bismarck, then Ashley during the same timeframe. And at times areas of negative EPV in the 800 to 850 mb layer. The HRRR is not exactly the same as the RAP but similar. Both show a couple of enhanced bands of heavier snow. One from around Watford City south and east into Dunn and Stark counties, and another from around New Town, south and east along Lake Sakakawea, to around Bismarck. When we say heavier snow we are talking 1 to 2 inches, and maybe a locally higher report or two, compared to a dusting to maybe a half inch. So overall, not terribly impactful, unless you`re driving through a heavy snow shower late tonight into early Monday. Also, with the very cold temperatures, normally wet roads this time of year may be icy tonight into Monday morning. This was the case earlier this evening. Wet roads around Williston are now Scattered ice based on the latest road report. With lows down into the teens tonight, expect some slippery and possibly partially snow covered roads for the morning commute. Used a blend of time lagged rap/hrrr with Official for the forecast pops through the early morning on Monday. Updated text products out shortly. UPDATE Issued at 636 PM CDT Sun Apr 12 2020 A quick update for pops. Latest blend of models brings area of snow showers currently around Williston, south and east to near Bismarck/Mandan around Midnight. Occasional moderate to at times heavy snow showers in the Williston area has resulted in a quarter to a half inch of accumulation on grassy and elevated surfaces. UPDATE Issued at 459 PM CDT Sun Apr 12 2020 Isolated snow showers have developed pretty much across the forecast area. Updated pops to reflect this. Currently more numerous snow showers are located across the northwest and north central and carrying some higher pops here, especially for the northwest. The northwest and west central will be the focus for higher pops into the early evening as the forcing associated with the shortwave trough mentioned in previous discussion. && .SHORT TERM...(This evening through Monday) Issued at 243 PM CDT Sun Apr 12 2020 Isolated to scattered snow showers/flurries will continue through the evening across much of western and central North Dakota as a weak shortwave pushes through the area. As a midlevel low closes off tonight over northern Manitoba, a stronger compact shortwave will rotate around it and into western North Dakota. This wave can currently be seen on water vapor satellite imagery along the Saskatchewan/Montana border. The NAM and GFS are in good agreement that a quick moving band of snow will accompany this feature tonight into Monday morning from around Williston to the Bismarck/Mandan area and finally down to the South Dakota border over the southern James River Valley. While the area of snow will be relatively small and residence time underneath will be brief, there is a signal that the strongest part of the band may exhibit a burst of moderate to heavy snowfall. Both the NAM and GFS show a deep layer of decent frontogenetical forcing (when looking at filtered 150km frontogenesis) ideally collocated with strong upper level Q-vector divergence (smoothed to cancel out the noise of the field in higher resolution grids) associated with this band. Further, very steep midlevel lapse rates will be in place with strong omega maxing out in the dendritic growth zone. Near negative EPV here suggests a slantwise instability component. Areas along and around this narrow band of snow can expect a quick half inch to inch of snow before all is said and done. A few areas could see slightly more based on the favorable dynamics forecast to be in place. The wave will quickly depart early on Monday but another weak wave will rotate around the parent midlevel low that will have drifted into Ontario by the afternoon. This weak wave will once again bring isolated to scattered snow showers across the area through the evening hours before diminishing. Winds will also remain breezy to windy out of the northwest through the period. .LONG TERM...(Monday night through Sunday) Issued at 243 PM CDT Sun Apr 12 2020 High pressure at the surface builds into the region Monday night, likely setting the stage for the coldest night of the week, with lows presently forecast in the teens. Cool weather will continue through the week, with a slow recovery in temperatures as flow aloft gradually turns more northwest. The 12z NBM guidance that was used for the official forecast calls for highs returning to the 50s and possibly even the 60s Friday through the weekend. However, the 12z GEFS members still show considerable spread with the deamplification of flow aloft and resultant amount of warming. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 937 PM CDT Sun Apr 12 2020 Scattered to numerous snow showers from Willisson to around Minot and Rugby, tapering to isolated to scattered from Dickinson to Bismarck and Jamestown. Began each TAF with a VCSH, except for KISN with ongoing snow showers as TAF begins. Expect a decrease in snow shower over central ND in the next hour or two. We do anticipate an areas of snow showers spreading from current location around Williston, southeast to around KBIS by around 05 UTC, then southeast toward South Dakota. This area may brush KDIK also. TAFS indicate a period of reduced visibilities at KDIK and KBIS tonight with these snow showers. Diurnally driven snow showers at KMOT will dissipate quickly this evening, and may linger at KJMS a bit longer. Generally VFR condition except in areas of moderate to heavy snow showers. Late tonight expect VFR conditions after snow shower pass. Northwest wind becomes breezy again Monday afternoon. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...TWH SHORT TERM...ZH LONG TERM...ZH AVIATION...TWH
Area Forecast Discussion
National Weather Service Boston/Norton MA
1002 PM EDT Sun Apr 12 2020 .SYNOPSIS... A powerful low will track across the Great Lakes late tonight and Monday, with heavy showers and scattered thunderstorms during Monday. Strong to damaging winds will likely impact the region as well. A cold front will swing through Monday evening, with improving conditions and diminishing west winds. Dry and seasonable weather on Tuesday. This is followed by cooler temperatures mid to late in the week. Several chances for showers mid to late in the week, but no washouts are expected. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... 10 PM Update... No major changes to the forecast in the latest update. Leading edge of the rain shield now in the Philadelphia area and moving steadily northeast. Good model agreement among deterministic and ensemble guidance for rain to overspread western MA/CT just after midnight and then into RI and eastern MA around daybreak (~ 6 am). Southerly flow beginning to increase with 22 kt at MVY and 26 kt at MQE. Winds will continue to increase overnight although strong to damaging winds hold off until late Mon morning and especially Mon afternoon. Previous discussion... Clouds will continue to thicken as they push across the region this evening, thanks to mid level westerly winds in place. In the meantime, long wave H5 trough will continue to dig across the Mississippi valley, which will cause the steering winds aloft to back to the SW. This will bring warm air across the region through the night so, after fall to the mid and upper 40s early, readings will rise through the remainder of the night. Most of the 12Z model suite continue to signal a strong H5 short wave in the SW flow moving toward the central Great Lakes during the night. Excellent lift also in place, so will see surface low rapidly deepen overnight. Strong low level jet also in place on the eastern side of this low, so may see S-SW winds increase after midnight with gusts up to 25-30 kt toward daybreak, highest along the S coast, Cape Cod and the islands. Leading edge of showers will push E, reaching western areas by around midnight, then shifting across the remainder of the region overnight. && .SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/... Monday... *** Strong to Damaging Winds Likely Monday afternoon *** *** Low risk of isolated flooding with 2"+ rainfall possible *** Strong Winds... 12Z NAM model continues to show very strong low level southerly jet moving across E Mass/RI during Monday, on the order of 90-100 kt at H85, with 50-75 kt winds at H925. Big question will be whether the low level inversion will break if surface temps become mild enough to bring the strong winds down. Model guidance has suggested that wind gusts could reach up to 50 to 60 kt as the low level jet passes prior to the cold front pushing eastward. Looks like the highest winds will occur from midday through Monday afternoon especially across central and eastern areas. May see gusts over 60 kt across the southern near shore waters. Still uncertain whether these winds will mix down due to colder air below H925 along the S coast. Will need to monitor the temperature trends during Monday. If increased mixing does work in at the surface, could see milder temps than currently forecast which may allow even stronger winds to mix down. However, based on the latest guidance, have upgraded to a High Wind Warning for all areas except Franklin county, where a Wind Advisory is in effect from midday on Monday into early Monday night. Heavy Rain... Models continue to signal anomalous moisture plume ahead of the strong Great Lakes system pushing across the region. PWATs up to 3 to 4 SD above seasonal normal will move across, highest across central and western areas. Noting the record rainfall from the SPC sounding climatology for April 13 is 1.32 inches at KCHH, with the April max rainfall of 1.55 inches. So, as mentioned in the previous discussion, could see areas of very heavy rainfall Monday morning into the afternoon. Current forecast suggests rainfall of 1 to 1.5 inches, possibly up to 1.7 inches across portions of N CT into W RI. Leaned toward the WPC guidance for QPF amounts. Some question whether winds may become a bit more SE across western areas, which could add an upslope component and locally heavier rainfall across the E slopes of the Berkshires. Latest update from WPC still keeps the region in a marginal risk for excessive rainfall on Monday. At this point, leaned toward the WPC guidance for QPF amounts on this package. So, will continue to monitor latest guidance for this potential. Monday night... As the strong low pushes NE across western Quebec as it deepens to a sub 980 hPa low, the trailing cold front will swing across the region Monday evening. The pressure gradient will relax, allowing winds to diminish as well. Will see SW winds gusting up to 40-50 kt across eastern areas early, but will diminish to 20-30 kt by around midnight though some higher gusts may linger across the higher inland terrain and along the coast a bit longer. Leftover showers will quickly shift offshore and weaken Monday evening. Clouds will also dissipate and shift offshore, so skies will become mostly clear especially across the interior after midnight. Expect temps to bottom out in the mid to upper 30s across the higher terrain to the mid-upper 40s along the coastal plain. && .LONG TERM /TUESDAY THROUGH SUNDAY/... Highlights... * Active pattern through the extended with several opportunities for light precipitation. No washouts expected at this point in time. * Temperatures trending downward into the middle of the week. Rebounding late in the week, but still remaining near to below normal. Details... Tuesday... A cutoff low will be located by James Bay/western Quebec early on Tuesday. This feature will rotate northward into northern portions of Quebec. This will keep New England under cyclonic flow. A weak mid level ridge will build into the Great Lakes. This will nudge a surface high into southern New England, which will bring dry and quiet weather. Will see westerly flow aloft which will advect colder air into the region at 925 hPa. This will bring some downsloping across the region, so have increased high temperatures a bit from the previous forecast. Nudged temperatures up to the 75th percentile of guidance as there are questions on how much cloud cover will be in place over the region. If skies are clearer than currently anticipated then temperature will need to be bumped up further. High temperatures will be in the 50s across southern New England. Expect cooler readings along the eastern slopes of the Berkshires. Good agreement amongst deterministic guidance for strong mixing. Lapse rates within the boundary layer are adiabatic roughly up to 1.5 km AGL. Right now have gusts of 15 to 20 kts. Not out of the question that we tap into gusts of 25 to 35 kts if we can completely mix down winds at higher elevations within the PBL. Tuesday Night through Wednesday... Cyclonic flow persists through this time period. Will see a shortwave trough embedded within the broader cyclonic flow start out in the Upper Mississippi River Valley Tuesday night and dig into the central Great Lakes by Wednesday morning. The trough will then lift into northern New England late on Wednesday. This feature will interact with the stalled out front extending from the Carolinas to well offshore of New England. Expect a broad low to develop and ride along the front. This will bring chances of rain showers with the best opportunity for these showers across the South Coast, Cape Cod and the Islands. Expect slight chances further to the north and west, but should be dry across central and western MA. Still good agreement amongst deterministic guidance with the GFS/ECMWF coming more in line with one another today, whereas the GEM keeps the front further offshore. Ensemble plumes show clustering of QPF roughly ranging from roughly a tenth of an inch to a quarter of an inch with the highest amounts expected over Nantucket and Marthas Vineyard. Flow aloft will become west northwesterly and advect colder air into the region. This will bring cooler readings to the region. Low temperatures heading into Wednesday will generally be in the 30s. The only exception is along the coast where lows will be around 40. High temperatures on Wednesday top out in the 40s across the region. Wednesday Night through Saturday... Cyclonic flow persists across southern New England through the rest of the extended. Confidence in the forecast decreases in this window as models begin to break down the timing and intensity of waves sliding through and in addition mass fields are significantly different from model to model and run to run. Due to the uncertainty have kept the NBM guidance through this window. Still appears that any precipitation will be light in nature as shortwaves quickly move through. High temperatures will be near to below normal during this timeframe with readings ranging from the 40s to low 50s. Low temperatures will be in the 30s. && .AVIATION /02Z MONDAY THROUGH FRIDAY/... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. 02z update ... no major changes. Leading edge of rain shield in Philadelphia area at 02z will overspread western MA/CT around 05z then into RI and eastern MA by 10z. Southerly winds will continue to increase overnight with LLWS increasing toward 12z with WS020/18050. Previous discussion below. ================================================================ Tonight...High confidence VFR initially at all terminals with ceilings gradually lowering tonight to MVFR as the lower levels moisten and precipitation moves in. A very strong low will deepen and lift as it moves into the central Great Lakes. This will bring low level wind shear to all terminals overnight as the low level jet strengthens. Somewhat uncertain if it will be more gusty at times as RAP, HRRR and NAM Bufkit soundings show things remain decoupled. Have kept gusts out of the forecast across interior locations, but kept gusts across coastal locations with the marine layer nearby. Southerly winds at 10-15 kts increasing to around 15-20 kts late. Gusts of 25-30kts by 12Z. Low level wind shear of 40-50 kts tonight. Monday...High confidence. Some uncertainty on how much/frequent the higher gusts mix down. Very strong low level wind shear at all terminals through the day. Expect values of initially 40-50 kts increasing to 60-80+ kts with the highest values expected along the South Coast of MA and RI. Very strong southerly winds with increasing gusts. Speeds of 15-25 kts during the morning increasing to 25-35 kts. Gusts of 25-30 kts increasing to 35-60 kts with the highest speeds along the South Coast. MVFR conditions deteriorating to IFR and there may even be spots of LIFR especially along the South Coast. Widespread showers, which may be heavy at times. Tried to time out the period of heavier shower activity with visibility reductions down to IFR. Not out of the question there could be periods of LIFR, but have not included in the latest TAF set. Scattered thunderstorms moving in late in the morning through the afternoon. Have not included a mention in the latest forecast as am uncertain on how widespread the activity will be. Monday night...High confidence. Showers end from W-E between 01Z to 05Z. Skies scattering out to VFR. S winds gusting up to around 50 kt across E coastal terminals early. Winds then shift to W and diminish overnight, though may see gusts up to 25-35 kt through around 04Z-06Z along the coast and across higher terrain. KBOS Terminal...High confidence in the TAF. KBDL Terminal...High confidence in the TAF. Outlook /Tuesday through Friday/... Tuesday: VFR. Breezy. Tuesday Night through Wednesday: Mainly VFR, with local MVFR possible. Slight chance SHRA. Wednesday Night: Mainly VFR, with local IFR possible. Slight chance SHSN. Thursday: Mainly VFR, with areas MVFR possible. Breezy. Slight chance SHRA. Thursday Night: VFR. Breezy. Friday: Mainly VFR, with local MVFR possible. Breezy. Chance SHRA. && .MARINE... *** Storm Warning in effect from Monday afternoon into Monday evening *** Tonight... Rapidly deepening low pressure moves across the central Great Lakes. S winds increase to 20-30 kt toward daybreak on Monday. Showers move in from W-E after midnight. Monday... Southerly winds continue to quickly increase. Expect winds up to 25-40 kt gusting up to 50-60 kt, highest during the afternoon. Heavy showers move across, along with scattered thunderstorms. Poor visibility in areas of fog. Seas build to 18-22 feet, highest on the southern open waters. Monday night... S-SW winds 25-35 kt gusting to 50 kt, highest across the eastern waters early, will shift to W and diminish. Gusts up to 25-35 kt linger after midnight, but should drop below small craft toward daybreak Tuesday. Seas up to 18-20 ft offshore and across the southern waters early, subsiding to 5 to 8 feet on the eastern waters and up to 11 ft on the southern outer waters by daybreak Tuesday. Outlook /Tuesday through Friday/... Tuesday: Winds less than 25 kt. Rough seas up to 12 ft. Tuesday Night: Winds less than 25 kt. Local rough seas. Chance of rain showers. Wednesday: Winds less than 25 kt. Areas of seas approaching 5 ft. Chance of rain showers. Wednesday Night: Winds less than 25 kt. Areas of seas approaching 5 ft. Thursday: Winds less than 25 kt. Areas of seas approaching 5 ft. Slight chance of rain showers. Thursday Night: Winds less than 25 kt. Areas of seas approaching 5 ft. Friday: Winds less than 25 kt. Areas of seas approaching 5 ft. Chance of rain showers. && .TIDES/COASTAL FLOODING... Southerly winds will intensify tonight and especially on Monday. The prolonged period of very strong southerly winds in combination with the Monday afternoon high tide across the South Coast and Narragansett Bay will lead to elevated water levels. Closely stuck to the Stevens Institute guidance and bumped up values within Narragansett Bay to more closely match this guidance. There is a wide envelope per the ensemble guidance in Providence, RI. Astronomical high tides will be around a MLLW of 4.2 feet during the afternoon. Expecting around a 2.5 to 3.5 ft surge, which will bring MLLW around 7 ft per Stevens Institute guidance. Though no coastal flooding is currently anticipated, this will need to be closely monitored in future forecast updates. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...High Wind Warning from noon to 7 PM EDT Monday for CTZ002>004. MA...High Wind Warning from 3 PM to 10 PM EDT Monday for MAZ013- 016>021. High Wind Warning from 3 PM to 7 PM EDT Monday for MAZ005>007- 014-015. High Wind Warning from noon to 7 PM EDT Monday for MAZ004- 008>012-026. High Wind Warning from 4 PM to 10 PM EDT Monday for MAZ022>024. Wind Advisory from noon to 8 PM EDT Monday for MAZ002-003. RI...High Wind Warning from 1 PM to 10 PM EDT Monday for RIZ003>008. High Wind Warning from 1 PM to 7 PM EDT Monday for RIZ001-002. MARINE...Storm Warning from 3 PM to 10 PM EDT Monday for ANZ231-232-251. Storm Warning from 2 PM to 10 PM EDT Monday for ANZ233-234-250- 254-255. Storm Warning from 4 PM to 8 PM EDT Monday for ANZ230. Storm Warning from 2 PM to 9 PM EDT Monday for ANZ236. Storm Warning from noon to 10 PM EDT Monday for ANZ235-237-256. && $$ SYNOPSIS...BL/EVT NEAR TERM...Nocera/BL/EVT SHORT TERM...EVT LONG TERM...BL AVIATION...Nocera/BL/EVT MARINE...BL/EVT TIDES/COASTAL FLOODING...
Area Forecast Discussion
National Weather Service State College PA
1113 PM EDT Sun Apr 12 2020 .SYNOPSIS... Locally heavy downpours are possible through the night as rain spreads across the area. Strong, gusty winds will also precede and occur in the wake of a cold front before subsiding Monday night. Severe thunderstorms may develop along and ahead of the sharp cold front as it sweeps through the area from Monday morning through the mid afternoon. Temperatures will drop sharply Monday afternoon and evening and trend below average for the rest of the week. && .NEAR TERM /UNTIL 8 AM MONDAY MORNING/... Rain now flowing northward nicely, but light so far. Everything is on track. Prev... Rain just a little slower moving, most likely due to the drier- than-expected air in the llvls. Lowered dewpoints in many places and delayed onset of rain. Elevated instability present later tonight (before sunrise), so also added mention of thunder to the southern tier and inch it northward thru 10 AM. Prev... Mid level altocu clouds and cirrostratus above will vary in amount and opacity this afternoon. A nearly east/west band of higher theta-E air in the 800-700 mb layer was leading to some light rain falling/spreading NNE from SW PA, while mainly sprinkles and virga were occurring further east, along and to the north of the Mason Dixon line Increasing southerly flow/LLJ will transport 1+ inch PWATs into central PA tonight. Expect widespread rain to overspread the area by midnight with locally heavy downpours possible into early Monday morning. The risk for flooding remains low with forecast rainfall amounts generally around a 0.50 inch or so ending 12Z Monday. Posted a Wind Advisory for late tonight through early Monday evening for the very strong southerly LLJ that will buffet mainly the ridge tops with 40 to 45KT gusts, but also create standing waves of strong wind gusts at the base of the first wave just to the north of the ridges with strong gap winds too. As a strong Cfront crosses the region later Monday morning through mid afternoon, we`ll see a transition to west- southwest wind gusts at the same speeds for much of the Central Ridge and Valley Region and Susq Valley, while greater 3 hourly sfc P-Rises of nearly 10mb and strong CAA across the NW Mtns and Laurels (Closer to the strong sfc low track across Lake Erie) will help to create wind gusts as high as 50 kts - warranting a High Wind Warning there (14Z Mon through 00Z Tue). && .SHORT TERM /8 AM MONDAY MORNING THROUGH 6 PM MONDAY/... Wind fields aloft really crank up into Monday morning with the southerly LLJ reaching 70-80kts or +4-5SD above the mean across the eastern half of the area. A very strong shear/modest CAPE environment is forecast ahead of a sharp cold front progged to sweep across CPA between ~14-20Z Monday. Assuming clouds breaks can develop in the wake of the overnight/early morning WAA rains, a significant risk of organized severe weather will exist with storms capable of damaging winds (primary threat) but also an isolated tornado or two. SPC has maintained its SLGT risk for Monday, including TOR Probs of 5% over much of our CWA. This is further supported by the latest, 18Z RAP that is on the more aggressive side with a nose of 2.5-3.5M2/S2 EHIs spreading north to the Central Mtns near KUNV by 15Z Monday, within the belt of 50-65KT South-SSW winds at 850 mb and about 75-100NM ahead of the Cfront. MU CAPE within this prefrontal, LLJ instability max will reach 1500-1800 J/KG during the late morning through early afternoon hours across the eastern half of the CWA, and will be associated with the primary threat of lower-topped, fast moving mini-supercells and bow echoes capable of the localized/enhanced wind damage and a few tornadoes. Fixed layer sig tor parameter peaks between 2.5 and 4 acrs the Scent Mtns through the Lower and Mid Susq valley between 15-18Z Monday. Plan to have plenty of eyes on the KCCX Dual Pol and regional 88Ds/TDWRs covering our SE Zones where the greatest SVR/TOR threat appears to be. Max temps will likely reach the L70s across the Lower Susquehanna Valley during the early afternoon and will peak in the 60s elsewhere. Temps will fall sharply across the NW half of the CWA and into the 40s-L50s by late afternoon in the wake of the cold front. && .LONG TERM /MONDAY NIGHT THROUGH SUNDAY/... A brief lull in the weather is expected Monday night into Tuesday, as the cold front pulls east of the area. A weak disturbance could brush the region with a bit of light rain or (becoming more likekly) wet snow Tuesday night into Wednesday as below normal temperatures continue. Medium range guidance continues to show an anomalous upper level trough over the Great Lakes and northeastern CONUS through the remainder of the week into next weekend, supporting a continued stretch of below normal temperatures. Another weak disturbance could bring a bit of light rain or wet snow across the area Wed night into Thurs, with both the ECMWF and GFS projecting a more substantial area of low pressure to impact the region Friday into Friday night with a return of breezy conditions. && .AVIATION /03Z MONDAY THROUGH FRIDAY/... Rain showers will overspread from southwest to northeast overnight. Prevailing MVFR conditions are expected with the best possibility of IFR at AOO, UNV, and the southeastern airfields before daybreak. Gusty winds out of the south and an approaching cold front will keep LLWS a threat through the morning on Monday. Potential for a line of severe thunderstorms accompanying the cold front between 10A and 2P on Monday. Have attempted to time out cold front and passage of storms in TAfs. Strong southerly gradient winds gusting up to 40 kts at times across the higher terrain and downwind (north) of the ridges will transition into strong WSW post cold frontal winds Monday (late morning west and early afternoon east) Tue-Wed...Increasing chance for rain/snow Tue night-Wed. Thu...Still a chance of rain and snow showers across the north and west. Fri...Rain possible with reduced cigs areawide. && .CTP WATCHES/WARNINGS/ADVISORIES... Wind Advisory from 4 AM to 8 PM EDT Monday for PAZ006-011-012- 018-019-025>028-034-035-037-041-042-045-046-049>053-056-058. High Wind Warning from 10 AM to 8 PM EDT Monday for PAZ004-005- 010-017-024-033. Wind Advisory from 4 AM to 10 AM EDT Monday for PAZ004-005-010- 017-024-033. Wind Advisory from 7 AM to 8 PM EDT Monday for PAZ036-057-059- 063>066. && $$ SYNOPSIS...Dangelo/Lambert NEAR TERM...Dangelo/Lambert/Steinbugl SHORT TERM...Steinbugl LONG TERM...RXR/Evanego AVIATION...Lambert/Banghoff
Area Forecast Discussion
National Weather Service Peachtree City GA
1000 PM EDT Sun Apr 12 2020 .UPDATE... Still on track for widespread severe storms during the remainder of this evening and into the overnight period. Have already seen some potential tornadic storms across the NW. In addition, training across these areas is leading to flash flood concerns as well. Wedge that was aiding in keeping things stable across the region has all but eroded away now, allowing for the CAPE values to increase from the south. Atmosphere over most of the area is now primed for the arrival of main event moving through central Alabama currently. Straight line winds look to be a major concern with hatched area and 45 percent contour from SPC now over a large portion of the area. But also still very concerned with tornado potential along the line as well with high dewpoint environment feeding into the line as it progresses east. Grids have all of this covered exceptionally well with all the severe and tor verbiage in there along with categorical pops. Will make some minor changes but overall, these grids will ride. Deese && .PREV DISCUSSION... /issued 742 PM EDT Sun Apr 12 2020/ PREV DISCUSSION... /issued 332 PM EDT Sun Apr 12 2020/ .INCREASED CONCERN OF SIGNIFICANT SEVERE WEATHER OUTBREAK LATE TODAY INTO EARLY MONDAY MORNING... SHORT TERM /Rest of today through Monday Night/... Things should ramp up quickly here for a significant outbreak of severe storms (possibly the strongest event in at least the last 2 to 3 years) having the big three main threats of strong long- track tornadoes, damaging winds, and large hail this afternoon into the overnight. Much of the western CWA remains in a Moderate Risk with the rest of the area in an Enhanced, though the storm threats could occur area-wide. All the recent convective development across the western and northern CWA has been tapping into mostly elevated instability, though concern is increasing with the evolution of a warm front/lingering wedge front across portions of north Georgia (currently extending near the Atlanta Metro to just south of Athens) as this may end up focusing some stronger rotating convection tapping into more surface based energy along with localized enhanced low level helicity and frontogenetic forcing on top of the ample upper forcing/jet dynamics. The HRRR continues to ramp up the Sig Tor Param along and south of this feature that could slowly lift northward this afternoon into evening and bulk shear vectors have strong veering, so will need to watch for discrete supercell and tornado potential even ahead of the main overnight expected storms. Hi-res CAM consensus continues to have expected intense convective zones/broken lines with embedded supercells pushing into the CWA after about 04z (midnight) tonight pushing eastward through the early morning hours. The HRRR indicates impressive swaths of updraft helicity along these storms interacting with over 400 m2/s2 of 0-1km SRH, so there is concern of some strong long-track tornadoes, even more dangerous given the nocturnal timing. Regardless there will be a widespread damaging wind threat with a robust 65 kt LLJ and 80-100 kts of bulk deep layer shear as the upper wave swings negative. Have continued with Flash Flood Watch across the far north where storm total QPF still looks to be in the 2-4 inch range. Also continuing the Wind Advisory as the enhanced southerly gradient winds will be strong especially as we get into the warm sector of the surface low. The storm threat looks to exit the southeastern CWA between 12-15z Monday and west to NW winds behind the front should gradually decrease during the day with clearing conditions. Baker LONG TERM /Tuesday through Sunday/... The forecast remains mainly on track through the extended period, with only minor changes made based on the latest guidance. The previous discussion follows... King PREV DISCUSSION... /Issued 740 AM EDT Sun Apr 12 2020/ LONG TERM /Monday Night through Saturday/... Region remains under a fairly active and progressive pattern through the extended forecast period. Period starts out mainly dry behind the strong system impacting the area today through early Monday. A short wave sweeps along the gulf coast region Tuesday bringing rain chances back into the forecast area, especially the southern portion of the area. Instability is marginal at best with limited chances for thunder with this system. Mainly dry for the latter half of the work-week with rain chances increasing again next weekend as another wave approaches. Temperatures remain relatively seasonal through the period. 20 AVIATION... 00Z UPDATE... Persistent wedge continues its influence over the ATL area terminals with IFR conditions continuing. Should see these rapidly transition to MVFR ahead of severe thunderstorm line. Did choose to add TEMPO to all sites to account for strong wind potential with line and have 35G45kts for most sites. This may need to be increased further with subsequent updates. Line timing is still on track for after 06Z for ATL and after 09Z for AHN and MCN. Conditions to clear fast behind the line although wind gusts should continue for several hours after. //ATL CONFIDENCE...00Z UPDATE... Medium on IFR duration. High on remaining elements. Deese && .PRELIMINARY POINT TEMPS/POPS... Athens 62 76 50 73 / 100 20 5 5 Atlanta 62 73 48 72 / 100 10 5 5 Blairsville 55 66 41 66 / 100 20 5 10 Cartersville 58 69 44 69 / 100 5 5 5 Columbus 65 80 53 80 / 100 10 5 10 Gainesville 59 71 48 69 / 100 10 5 5 Macon 65 81 53 79 / 100 30 5 10 Rome 58 67 44 68 / 100 5 5 5 Peachtree City 62 75 48 74 / 100 10 5 5 Vidalia 68 84 60 83 / 90 80 10 30 && .FFC WATCHES/WARNINGS/ADVISORIES... Wind Advisory until 6 AM EDT Monday for the following zones: Baldwin...Banks...Barrow...Bartow...Bibb...Bleckley...Butts... Carroll...Catoosa...Chattahoochee...Chattooga...Cherokee... Clarke...Clayton...Cobb...Coweta...Crawford...Crisp...Dade... Dawson...DeKalb...Dodge...Dooly...Douglas...Emanuel...Fannin... Fayette...Floyd...Forsyth...Gilmer...Glascock...Gordon... Greene...Gwinnett...Hall...Hancock...Haralson...Harris...Heard... Henry...Houston...Jackson...Jasper...Jefferson...Johnson... Jones...Lamar...Laurens...Lumpkin...Macon...Madison...Marion... Meriwether...Monroe...Montgomery...Morgan...Murray...Muscogee... Newton...North Fulton...Oconee...Oglethorpe...Paulding...Peach... Pickens...Pike...Polk...Pulaski...Putnam...Rockdale...Schley... South Fulton...Spalding...Stewart...Sumter...Talbot... Taliaferro...Taylor...Telfair...Toombs...Towns...Treutlen... Troup...Twiggs...Union...Upson...Walker...Walton...Warren... Washington...Webster...Wheeler...White...Whitfield...Wilcox... Wilkes...Wilkinson. Tornado Watch until 11 PM EDT this evening for the following zones: Bartow...Catoosa...Chattooga...Cherokee...Dawson... Fannin...Floyd...Gilmer...Gordon...Murray...Pickens...Polk... Walker...Whitfield. Flash Flood Watch until 8 AM EDT Monday for the following zones: Catoosa...Chattooga...Dade...Dawson...Fannin...Floyd...Gilmer... Gordon...Lumpkin...Murray...Pickens...Towns...Union...Walker... White...Whitfield. && $$ SHORT TERM...Deese LONG TERM....King AVIATION...Deese
Area Forecast Discussion
National Weather Service Grand Rapids MI
1053 PM EDT Sun Apr 12 2020 LATEST UPDATE... Update .SYNOPSIS... Issued at 328 PM EDT Sun Apr 12 2020 - Stormy Monday - Cold Tuesday through Friday && .UPDATE... Issued at 1050 PM EDT Sun Apr 12 2020 We did add some fog to the area for tonight...especially over Lake MI. The latest HRRR guidance does show a risk for thicker fog for a period tonight in the nearshore waters. We added the risk to the HWO as well. && .DISCUSSION...(This evening through next Sunday) Issued at 328 PM EDT Sun Apr 12 2020 - Stormy Monday Rain moves in this evening with some elevated instability after midnight, greatest across the southern half of the forecast area where we will keep a slight chance of thunder. Then we are dry slotted Monday morning before some wraparound rain/shower arrives by afternoon. The big story continues to be the wind as we expect gusts over 50 mph by late morning into early evening with mixing heights around 4 to 5 kft during that time able to tap 45 knot winds. We have issued a wind advisory although some gusts to 60 mph are still possible, most likely across the northeast zones where surface pressure gradient is strongest as the low deepens over Lake Huron. The low pulls away Monday night with winds decreasing. - Cold Tuesday through Friday The airmass that follows the low is more typical of February than April with 850 mb temps below minus 10C across central Lower Michigan on Tuesday and Wednesday. Temperatures should be stuck in the 30s on Tuesday and Wednesday afternoons and dropping into the lower to mid 20s at night. Along with the cold comes the chance for light snow as a minor sfc waves moves across the baroclinic zone to our south. We will also have to watch for a more organized low scooting through the ohio valley late in the week. Some snow or mixed precip could be across our central and southern zones then. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 723 PM EDT Sun Apr 12 2020 As the storm system nears tonight...the impactful aviation conditions will be on the increase. Low clouds will eventually overspread the TAF sites in Southwest Lower MI with IFR or lower likely later tonight. In addition the showers will temporarily lower VSBYS...especially after midnight. Then for Monday the wind shifts early and increases considerably. Gusts over 35 knots are forecasted for all sites. VSBYs and ceilings will be on the increase during the day as drier air works its way in from the west. && .MARINE... Issued at 328 PM EDT Sun Apr 12 2020 No changes to the Gale Warning and Coastal Flood Warning. Still expecting northwest gales over 40 knots from Monday morning into the evening with 10 to 14 foot waves. The highest waves and worst erosion and coastal flooding is expected from Grand Haven to South Haven. Conditions will begin to improve Monday night. && .HYDROLOGY... Issued at 328 PM EDT Sun Apr 12 2020 QPF has decreased with this forecast update to a half inch or less although some higher amounts are well within the realm of possibility. We expected some modest rises on the rivers this week but not expecting flooding. SOme sites to watch are those that are near bankfull already like Ionia, Holt, Maple Rapids and Vicksburg. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...Lakeshore Flood Warning from 5 AM Monday to 5 AM EDT Tuesday for MIZ037-043-050-056-064-071. Wind Advisory from 8 AM to 8 PM EDT Monday for MIZ037>040- 043>046-050>052-056>059-064>067-071>074. LM...Gale Warning from 5 AM Monday to 5 AM EDT Tuesday for LMZ844>849. && $$ UPDATE...MJS SYNOPSIS...Ostuno DISCUSSION...Ostuno AVIATION...MJS HYDROLOGY...Ostuno MARINE...Ostuno
Area Forecast Discussion
National Weather Service Lincoln IL
901 PM CDT Sun Apr 12 2020 .SYNOPSIS... Issued at 254 PM CDT Sun Apr 12 2020 Showers and scattered thunderstorms will accompany a cold front, which will sweep across Illinois tonight. As the front passes, winds will significantly increase, and will gust from 40 to 50 mph late tonight into Monday. This will mark the start of much cooler conditions, which will persist most of the week, and resulting in below freezing temperatures each night beginning Monday night. && .UPDATE... Issued at 900 PM CDT Sun Apr 12 2020 A cold front has reached roughly the Illinois River this evening, with a fine line of isolated heavy showers and a trailing region of widespread rain trailing behind. Instability has almost totally diminished, so have trimmed out thunder mention except for a slight chance around Jacksonville area mid evening and around I-70 southward from midnight to 4 am. Otherwise, forecast is on track with temperatures dropping dramatically into the 30s behind the front and strong northwest winds 20-30 mph with gusts 40-50 mph developing overnight. && .SHORT TERM...(This evening through Monday) ISSUED AT 254 PM CDT Sun Apr 12 2020 Earlier clear slot from Missouri into northern Illinois is still visible on satellite imagery, but high clouds have spread over top of it. This has allowed temperatures to reach the mid 60s toward Galesburg, though upper 50s/lower 60s prevail elsewhere early this afternoon. After a few hours of dry conditions, showers are starting to increase again, which has been hinted at by recent HRRR runs. Showers/storms are also starting to lift northeast of the Ohio River, as a shortwave ejects out of Missouri. Main synoptic front analyzed just west of Cedar Rapids IA into east central Kansas, and is expected to begin entering the western CWA just after sunset. Highest PoP`s are aligned with its passage, with the front near the Indiana border by about 3 am. Associated rainfall should largely be out of the area by sunrise. Behind the front, winds quickly ramp up and be gusting from 40-50 mph by early morning. In collaboration with neighboring offices, have extended the Wind Advisory until 7 pm Monday, though conditions south of I-72 will be diminishing a bit by mid afternoon. .LONG TERM...(Monday night through Sunday) ISSUED AT 254 PM CDT Sun Apr 12 2020 Longer range focus will be on the much cooler conditions, with nightly temperatures at or below freezing. Vegetation across the south half of the forecast area has advanced far enough that frost/freeze headlines will likely be needed at various points. Improvement is expected by next weekend, as highs return to the 60s. With the broad northwest flow, weak disturbances through mid week will be capable of squeezing out some precipitation at times, with the best chance late Tuesday and early Wednesday. Further out, as the flow starts to become more zonal and split, an elongated west-east boundary will provide the focus for additional precipitation. The GFS is standing alone with a deep wave in the northern flow, resulting in a deep surface system and raw snowfall projections of several inches across the northern CWA Thursday night and Friday. Having a hard time buying into this, and will mainly stick with a rain mention, with rain/snow across the north. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 640 PM CDT Sun Apr 12 2020 MVFR conditions are predominant across central IL early this evening, with a few breaks in the cloud cover just ahead of a cold front approaching the Mississippi River. This front and associated showers and thunderstorms will sweep across central IL late this evening, bringing an abrupt wind shift to strong NW winds, a return to IFR and MVFR cigs, and some MVFR vsbys as well. SHRA will gradually taper off after 06-08Z, while MVFR cigs are expected to return by 09Z-10Z, then gradually lift to VFR by 15Z-18Z. Winds S around 10 kts until 05-08Z becoming NW 20-25 kts with gusts 35-40 kts from around 09-15Z. Winds should diminish several kts from 18Z-24Z. && .ILX WATCHES/WARNINGS/ADVISORIES... Wind Advisory from midnight tonight to 7 PM CDT Monday for ILZ027>031-036>038-040>057-061>063-066>068-071>073. && $$ UPDATE...37 SYNOPSIS...Geelhart SHORT TERM...Geelhart LONG TERM...Geelhart AVIATION...37
Area Forecast Discussion
National Weather Service Louisville KY
948 PM EDT Sun Apr 12 2020 .Forecast Update... Issued at 948 PM EDt Sun Apr 12 2020 Currently in a precipitation lull except for just a few showers in south-central KY. Deep convection is ongoing in the warm sector across the Deep South and along the cold front in Arkansas. An elongated area of sfc low pressure is oriented roughly along the Mississippi River Valley. Sfc low pressure is still forecast to deepen to the northeast overnight just downstream of a vigorous, compact shortwave trough. The severe threat overnight is still very conditional on any available instability, and would also say that threat appears more marginal now. Any developing sfc based instability will be tied to the sfc low`s ability to draw warm, moist air further north. Sfc dewpoints are currently running in the mid to upper 50s, with upper 50s confined to the Lake Cumberland region. Based on the latest hi-res data, think we will see dewpoints rise into the upper 50s/lower 60s. This is a strong system with impressive low level wind fields, so a modest dewpoint rise does make sense. Will have to watch a couple areas of convection, the first being heavier showers moving northeast from Middle TN. That activity will spread into southern KY around 930-1000 PM CDT. Think we could see some strong wind gusts, but instability will still be quite meager in the 03-04z time frame. The second area to watch is the line of storms along the front in Arkansas. It does appear that convection will be able to sustain itself for at least another 2-3 hours, but the HRRR generally suggests a somewhat weaker band of showers (still of convective nature) in the 07-13z time frame. This window, generally along and behind the actual front, may bring a more widespread potential for strong wind gusts. Fcst soundings show moist adiabatic low level lapse rates along the front, with a little elevated instability. So these showers, coupled with the better mixing and strong PGF immediately behind the front, will likely result in at least 40-50 mph winds. Issued at 619 PM EDT Sun Apr 12 2020 Widespread moderate rain has overspread the region in an area of strong warm air advection and on the nose of the max 925-850 mb moisture transport currently over TN and AL. Fortunately, current sfc based instability is nil. We are watching one narrow convective line push northeast across Middle TN, but this feature is likely to remain sub-severe when it moves NE across the Lake Cumberland region. Low to mid level wind fields and shear profiles are quite impressive, but the lack of instability will make it quite difficult to realize severe wind gusts. KBNA had a gust to 30 kts from 280 when the line crossed. Widespread clouds and precip have helped keep instability to a minimum. Sfc dewpoints are running in the low to mid 50s as of this writing. While dewpoints could surge a few degrees in the Lake Cumberland region over the next 1-2 hours as that narrow convective line approaches, it likely won`t be enough to significantly increase the severe threat. So overall, the severe threat with this first wave appears to be marginal. There may be some minor flooding issues in that region as well, including the counties of Monroe, Cumberland, Clinton, and Russell. Dual-pol radar estimates around 1.5 inches of rain has fallen thus far across a good chunk of those counties. The relatively brief heavier convective rates upstream may very well produce ponding of water and general minor flooding in low lying areas and any areas typically susceptible to flooding. But with a sizable lull not far off behind this first wave, think the flash flood threat is low/very isolated at this time. && .Short Term...(This evening through Monday) Issued at 305 PM EDT Sun Apr 12 2020 ...Strong to Severe Storms Possible Tonight... Main focus remains on tonight as strong to severe storms will be possible over the area as a compact shortwave trough ejects out of the lower MS Valley and pushes across the OH Valley overnight. Besides some scattered shower activity earlier today, this afternoon has been mostly dry and overcast, although a more widespread area of light to moderate showers is now beginning to push northward into southern KY, with some rumbles of thunder and lightning possible. Farther south, an ongoing MCS with a history of producing tornadoes, damaging winds, and hail is moving northeast across LA/AR/MS. As we look to our own severe potential tonight, a lot of uncertainty remains as our ability to destabilize will hinge on how much these southern storms rob us of sufficient instability and moisture. The SPC`s southward pull of the Enhanced Risk to about the KY/TN border reflects the lowered confidence in our ability to destabilize later tonight. Expect showers and storms to overspread the area this evening and into tonight as we see increasing lift under a 50-60 kt LLJ ahead of the ejecting shortwave. Model soundings indicate any instability would likely remain elevated at this point, although wind profiles will be quite impressive with 0-6 km Bulk Shear values of 50-60 kts and 0-3 km ESRH of 200-400 m2/s2. Expect areas of heavy rainfall as PWATs increase to around 1.5 inches, and some embedded rumbles of thunder will also be possible. Another wave of showers and storms will be possible overnight as an initial area of convection is expected to develop near the surface low over southeast OK later this afternoon and move northeastward, reaching our region after Midnight EDT. With favorable wind profiles still in place, the question mark will remain whether or not we are able to destabilize at all. If any storms this evening and overnight are able to become surface based, damaging winds will be the main threat, although an isolated tornado cannot be ruled out. The most likely area for seeing any surface based instability will be across southern KY, where stronger moisture and instability advection may occur. Behind storms, expect strong wind gusts across the region starting late Sunday night and into Monday morning as the pressure gradient tightens around the departing low. Wind gusts of 40-50 mph will be possible, with peak winds being observed early Monday morning between 10-12Z. The strongest winds are expected to occur over south- central KY, where wind gusts will approach High Wind Warning Criteria. However, confidence is not high enough at this time to upgrade the Wind Advisory. Precipitation chances will end from west to east Monday morning behind the cold front, leaving us cool and dry for the rest of the day. Winds will gradually decrease through the afternoon as the pressure gradient relaxes and a surface high begins to nudge its way into the region. Temperatures will fall into the mid 40s to low 50s by late morning and generally remain in this range through the afternoon. .Long Term...(Monday night through Sunday) Issued at 305 PM EDT Sun Apr 12 2020 Winds will die down Monday evening, but even with temps dropping into the mid 30s there will be enough cloud cover to limit any frost concerns Tuesday morning. Much of the upcoming work week will be unseasonably cool as broad upper trofiness covers most of the eastern CONUS. Could be a few disturbances in the quasi-zonal flow, but POPs will be limited due to uncertainty in the timing. Any mornings with precip chances will pose a precip type issue, while the drier mornings could involve frost if skies are clear. Plenty of bust potential with clouds so will not make any specific frost mentions yet. A sharper shortwave trof will bring better precip chances on Friday, and could also involve thunder. That system will be followed by a Pacific air mass, so temps will recover to near climo for next weekend. && .Aviation...(00Z TAF Issuance) Issued at 757 PM EDT Sun Apr 12 2020 Widespread rain has cleared out of BWG/HNB/SDF and will quickly clear LEX over the next half hour. There may still be a few showers around through the evening, but the bulk of precipitation will hold off until a second round late tonight/early Monday. In the meantime, the main challenge will be low ceilings mostly in the low MVFR or IFR range at BWG/SDF/HNB. LEX may actually go back to VFR for a while this evening. Winds will be steady out of the SE. A strong surface low will move through the area through the overnight with strengthening S and the W surface winds as it passes. The W winds will likely gusts up above 45 mph at times, with more common sustained gusts above 35 mph. There may be a few showers/storms associated with this feature between Midnight and dawn, but overall confidence is fairly low. Best chance for low MVFR and even IFR ceilings will be at BWG/SDF/HNB through the overnight. Once winds go to a W direction, expect rapid improvement in ceilings back to VFR by late morning or early afternoon. Winds will gradually decline through the afternoon, but will remain gusty through the end of the cycle. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...Wind Advisory from 2 AM EDT /1 AM CDT/ to 2 PM EDT /1 PM CDT/ Monday for INZ076>079-083-084-089>092. KY...Wind Advisory from 2 AM EDT /1 AM CDT/ to 2 PM EDT /1 PM CDT/ Monday for KYZ023>043-045>049-053>057-061>067-070>078-081- 082. && $$ Update...EBW Short Term...JML Long Term...RAS Aviation...BJS
Area Forecast Discussion
National Weather Service Memphis TN
833 PM CDT Sun Apr 12 2020 .DISCUSSION... Skies are cloudy across much of the Mid-South this evening with temperatures from the mid 50s to around 70 degrees. The first area of thunderstorms is finally moving out of the eastern side of the Mid-South with another large area of thunderstorms about to enter the region from the west. Some of these thunderstorms could produce damaging winds and large hail so a Severe Thunderstorm Watch has been issued for roughly the western half of the Mid- South until 1 AM CDT. ARS && .PREV DISCUSSION... /issued 412 PM CDT Sun Apr 12 2020/ UPDATE...Updated to remove the Tornado watch from North Mississippi. Redevelopment looks questionable at this time. Adjusted pops/weather accordingly. 30 PREV DISCUSSION... /issued 223 PM CDT Sun Apr 12 2020/ DISCUSSION... SEVERE WEATHER IS STILL POSSIBLE THIS AFTERNOON AND EVENING... A tornado watch remains in effect for North Mississippi. The last few HRRR runs backed off of the 2nd round of thunderstorms this evening, but has now increased coverage once again. However, the surface low that was once well defined, tracking just South of Memphis is much more diffuse as it tracks into West TN. The warm front remains to our South but should begin to surge North over the next few hours ushering in mid-60 degree dew points into portions of North Mississippi. As this deeper moisture arrives, a shortwave trough and 70kt mid level jet will shift across the area. Low level shear remains impressive, 0-1km SRH in excess of 400 m2/s2 should be more than sufficient to support supercellular storms capable of producing tornadoes and widespread damaging wind. The main limiting factor will be surface based instability, which will remain limited until the warm front surges North. The highest potential for a strong long tracked tornado will likely be right along or just North of the warm front before sunset. It is highly uncertain if additional storms will develop along the cold front but if they do, conditions will be favorable for fast moving short lived tornadoes as well as damaging wind. By Midnight, the threat of any severe weather should be over. Cooler conditions will arrive tomorrow. Expect temperatures around 15 degrees below normal Monday and Tuesday with highs in the 50s followed by a warming trend Wednesday and Thursday. By Thursday we should see highs in the middle to upper 60s across most of the Midsouth. There could be frost across portions of West Tennessee, the Missouri Bootheel and Northeast Arkansas Tuesday and Wednesday mornings. A broad trough will deepen over much of the Eastern US Early in the work week, a weak disturbance rounding the base of the trough could result in a few light showers Tuesday, but otherwise dry conditions are expected through Friday. Expect near to slightly below normal temperatures Friday into the weekend. No organized storm systems are expected though it looks like a few additional showers are possible Friday night. 30 && .AVIATION... 00Z TAF cycle Low clouds will continue to cover much of the Mid-South tonight and will remain through the overnight hours. Showers and thunderstorms are moving across portions of north Mississippi at this time. Additional showers and thunderstorms will move into the region late tonight. Winds will be mainly from the south at 10 to 15 knots this evening before gradually shifting to the west and increasing to 15 to 20 knots and gusty overnight. ARS && .MEG WATCHES/WARNINGS/ADVISORIES... AR...Flash Flood Watch until 1 AM CDT Monday for Clay-Craighead- Crittenden-Cross-Greene-Lee AR-Mississippi-Phillips- Poinsett-St. Francis. Wind Advisory until 7 AM CDT Monday for Clay-Craighead- Crittenden-Cross-Greene-Lee AR-Mississippi-Phillips- Poinsett-St. Francis. MO...Flash Flood Watch until 1 AM CDT Monday for Dunklin-Pemiscot. Wind Advisory until 7 AM CDT Monday for Dunklin-Pemiscot. MS...Flash Flood Watch until 1 AM CDT Monday for Alcorn-Benton MS- Calhoun-Chickasaw-Coahoma-DeSoto-Itawamba-Lafayette-Lee MS- Marshall-Monroe-Panola-Pontotoc-Prentiss-Quitman- Tallahatchie-Tate-Tippah-Tishomingo-Tunica-Union-Yalobusha. Wind Advisory until 7 AM CDT Monday for Alcorn-Benton MS-Calhoun- Chickasaw-Coahoma-DeSoto-Itawamba-Lafayette-Lee MS-Marshall- Monroe-Panola-Pontotoc-Prentiss-Quitman-Tallahatchie-Tate- Tippah-Tishomingo-Tunica-Union-Yalobusha. TN...Flash Flood Watch until 1 AM CDT Monday for Benton TN-Carroll- Chester-Crockett-Decatur-Dyer-Fayette-Gibson-Hardeman- Hardin-Haywood-Henderson-Henry-Lake-Lauderdale-Madison- McNairy-Obion-Shelby-Tipton-Weakley. Wind Advisory until 7 AM CDT Monday for Benton TN-Carroll- Chester-Crockett-Decatur-Dyer-Fayette-Gibson-Hardeman- Hardin-Haywood-Henderson-Henry-Lake-Lauderdale-Madison- McNairy-Obion-Shelby-Tipton-Weakley. && $$
Area Forecast Discussion
National Weather Service Miami FL
733 PM EDT Sun Apr 12 2020 .Aviation... There could be periods of MVFR conditions tonight as some lower cloud cover tries to develop across the region. Southeasterly wind flow will continue overnight at 10 to 15 knots. These winds will shift to a more southerly direction on Monday and increase in speed to 15 to 20 knots with higher gusts. Dry conditions should prevail across all terminals on Monday. && .Update... Mainly dry conditions will occur across the region tonight as a breezy southeasterly flow continues across South Florida. The winds will begin to shift to more of a southerly direction on Monday, however, the speeds will increase and range between 15 and 20 mph with some higher gusts especially later in the morning and into the afternoon hours. Mainly dry weather will remain in place across South Florida due to the area of high pressure located in the western Atlantic. Warm temperatures will prevail on Monday as highs will range from the upper 80s across the east coast to the mid 90s across the interior sections. && .Prev Discussion... /issued 232 PM EDT Sun Apr 12 2020/ Short Term... Today and tonight... Looking at the potential for convection, models are mixed. Some models show little in the way of any convection over South Florida. Then other models, including the GFS and the HRRR show the potential for convection across portions of the area, especially in the Lake region. Currently, there is only a slight chance in the forecast. The question is if convection will be able to initialize or not. The GFS was more optimistic with around 1.75 inches over much of the area for the day. the NAM was somewhat drier this morning, then showed some moisture advecting into the area this afternoon. Looking at the visible sat imagery, there appears to be a slot of drier air along the Gulf coast, with higher amounts of moisture over the remainder of the CWA, as shown by the amount of cloud cover. The frontal boundary, that was to the south currently appears to be connected with the demarcation of the cloud/moisture field, and is lifting north as a warm front. Temperatures behind the front are a few degrees higher than to the east of the front. With the front providing some weak lift in the western Lake region, along with models indicating lapse rates from the sfc to about 3km at 8.3 C/km, convective initiation is possible. However, at 500mb, there is a ridge building, with minor height rises at that level. There is some shear, with the effective shear at 45kts on the NAM model sounding. The helicity is weak, at lower than 100 and the freezing level should be around 14500 ft. The model sounding is also showing some features, such as an inverted V and a dry layer at around 700mb. At about 350mb, there is a jet, with wind around 65kts. Putting this all together, it indicates that if convection is able to initiate, there is a potential for hail, at least small hail, if not moderate size, but still under 1 inch. The inhibiting factor in large hail possibility would be how strong the jet is. At 65 kts, it may cause too much lean to any storms for the updraft to keep any hail stones within it long enough to grow to larger than 1 inch. but again, that is dependent on the exact speed and location of the updraft in each storm. So there would still be a non zero chance of large hail. Lending to aid in this would be the NCAPE of over.2, indicating some decent vertical velocity possible with the storms. Now, along with that, the stronger vertical velocity may allow some of the cores of any storms that are able to develop to tap into the higher speeds aloft. The 500mb temp is forecast to be around -8.4C, indicating at least a cool, if not a cold pool aloft. If the storm is able to develop with the core into the cold pool and higher wind speeds, any downbursts could contain wind speeds of at least 60kts, especially with the inverted V sounding. Again, this is all conditional, and based on convection being able to initiate. The chances are very small, but they are non zero for this afternoon and evening. One other parameter that could come into play is the Lake shadow effect. This may cause some differential heating, which could aid in the development, and also may allow for a boundary strong enough to allow an isolated waterspout to be possible. Again, there is a large amount of uncertainty with any of the above scenarios occurring, so it is very possible that it does not materialize. But, if convection is able to occur in the Glades and Hendry County area, there is a potential for some strong to severe storms to materialize. Once we lose daytime heating and the front has moved into central Florida, the remainder of the night should be dry, with a continued southeast wind. Tomorrow and tomorrow night... The high pressure sitting to the east is progged to maintain the south southeast wind. The models are showing that the weather should remain dry through Monday night, with a warming trend in place. Highs Monday are forecast to be in the upper 80s along both coasts, and in the mid 90s for the interior areas. Lows are forecast to be in the upper 60s to mid 70s along the coasts. Long Term (Tuesday through Saturday)... The cold front enters the peninsula of Florida on Tuesday morning as the parent low pressure system moves northward into Canada. The front will end up stalling somewhere in north central Florida before the next impulse arrives on Wednesday. This impulse will not be enough to push the boundary south of Central Florida. With the boundary located to the north of the area, temperatures will continue to remain warm with rain chances remaining non-zero each day. As the next mid-level moves across the central United States, a surface low will develop over the plains and enter the Ohio River Valley and Great Lakes regions on Friday. This system will provide reinforcement to the stall boundary that will propel it southward again. With this boundary moving closer, shower and thunderstorm chances will increase to close out the week and kick off the weekend. Uncertainty remains in the location and timing of the frontal boundaries in the long term period of the forecast. A more progressive or southward stall could bring increased unsettled weather to the region along with cloud cover which could allow for slightly cooler temperatures than forecast. On the flip side, less southward progress than forecast could keep the region on the warm side of guidance with the potential for record heat and parched ground conditions. Will need to monitor the evolution of these features over the week to see how they will influence any mesoscale factors that come into play like remnant boundaries from previous convection, sea breeze development and progression, and the potential for enhanced convection. Marine... Breezy conditions are forecast to continue, which may bring hazardous marine conditions to the South Florida waters at least through Monday morning. Conditions are forecast to begin to improve Monday under high pressure. However, there is a potential the wind may not subside quick enough and the Small Craft Advisory, currently in effect through Monday morning, may need to be extended. Otherwise, quiet weather is forecast through the middle of the week, with chances of rain increasing for the end of the week, mainly for the Atlantic waters. Aviation... Abundant cloud cover across South Florida may bring some brief IFR conditions as cigs briefly drop. However, breezy conditions will cause the cloud cover to vary fairly rapidly though the night. There is a potential for SHRA or TSRA in the Lake region through the evening hours. Tomorrow should see dry weather, with the wind becoming more southerly and remaining breezy. Beach Forecast... Breezy conditions out of the southeast, are bringing enhanced risk of rip currents for the Atlantic coast. There is a high risk of rip currents today, and possibly tomorrow, although tomorrow should see conditions begin to improve. Even so, the risk of rip currents may continue to be enhanced through the middle of the week. && .Preliminary Point Temps/PoPs... West Palm Beach 76 90 74 88 / 0 0 10 20 Fort Lauderdale 78 88 77 87 / 10 0 10 10 Miami 78 88 76 88 / 0 0 10 10 Naples 76 88 74 89 / 0 0 0 10 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...High Rip Current Risk through Monday morning for FLZ168-172-173. AM...Small Craft Advisory until 8 AM EDT Monday for AMZ610. Small Craft Advisory until 8 AM EDT Monday for AMZ630-650-651- 670-671. GM...Small Craft Advisory until 8 AM EDT Monday for GMZ656-657-676. && Update...55/CWC Aviation...55/CWC
Area Forecast Discussion
National Weather Service Marquette MI
1109 PM EDT Sun Apr 12 2020 .UPDATE... Issued at 1108 PM EDT SUN APR 12 2020 No major changes have been made to the fcst this evening. A little concerned that the western fcst area could underperform on snow totals as radar trends indicate heavier pcpn will end up a bit farther e than anticipated, which evening HRRR runs and incoming 00z models indicate. Strengthening winds/upslope later tonight/Mon morning is a plus to enhance accumulations, but opted to cut back snow accumulations a couple of inches over the w given the eastward shift of heavier synoptic pcpn. Given the eastward shift, total snow accumulations were nudged up 1-2 inches in a corridor from western Alger county to northern Menominee County. Interesting item of note for later Monday will be the sfc trof/enhanced convergence zone extending from well nw of Thunder Bay, Ontario se across the Keweenaw to Alger County. Recent days model runs have consistently indicated this sfc trof, though in varying locations. Last 12hrs of model runs are converging on the trof extending across Keweenaw County to Alger County. Will be a feature to watch late Mon aftn/evening for intense snowfall. && .SHORT TERM...(This evening through Monday) Issued at 450 PM EDT SUN APR 12 2020 WV imagery and RAP analysis indicated a mid/upper level trough from northern Manitoba through the western Plains resulting in sw flow through the western Great Lakes. A vigorous southern stream shortwave was lifting northeast from OK/TX. A 140 knot 300 mb jet streak was draped through northwest Ontario. At the surface, an inverted trough extended to northern Lower Michigan from a 998 mb low over eastern OK. Upper level div from the right entrance of the Ontario jet and the associated broad area of deep isentropic lift, supported heavy pcpn from IA and se MN into Upper Michigan. Moderate to heavy snow was observed northwest of an IMT-RST line with rain to the south. Tonight, Continue strong isentropic lift with strong 50 knot flow/moisture transport bringing 295k-300k level(around 700 mb) mixing ratio values of 5g-6g/Kg toward Upper Michigan. Expect a period of very heavy snow tonight with impressive QPF to near 1.5 inch north central where lake and orographic enhancement is strongest. Values closer to 0.8 inch are expected through most of the rest of upper Michigan. The relatively wet snow with snow/water ratios near 10/1 will result in widespread snow totals of from at least 8 to 16 inches. Forecast soundings along with Models consensus Bourgouin energy values support mainly rain over the east with a pivoting band of mixed fzra/ra and sleet into the south and east central and snow over the west half. Temps near or only slightly below freezing should limit ice accumulation to around a tenth of an inch despite the heavy pcpn amounts. Monday, the deepening low pressure center over eastern Upper Michigan will continue to deepen and lift to the northeast. Any lingering mixed pcpn over the east will quickly shift east as the colder air moves in early. The very tight pressure gradient will support winds gusting to 40-50 mph, per forecast soundings momentum transfer prog. Although the support for the heavier pcpn will diminish during the morning as the stronger 700-500 mb fgen shifts to the east, lake enhance snow whipped by the strong winds will result in very low vsby with local whiteout conditions possible. Additional snow totals should remain in the 3 to 6 inch range, highest over the Keweenaw and north central. Amounts of around an inch or less are expected over the south. Wave heights of up to 15-20 ft will also result in some lakeshore flooding and beach erosion for locations exposed to the north winds. .LONG TERM...(Monday night through Sunday) Issued at 335 PM EDT SUN APR 12 2020 The main focus in the extended is the lingering lake-effect snow band that models continue to resolve across parts of the northwest wind snow belts Tuesday night through early Wednesday morning. Otherwise, the extended with feature well-below normal temperatures through at least the end of the week as numerous shortwaves rotate down across the region and advect in weak, reinforcing shots of cold air. These shortwaves arriving on a nearly daily basis will also allow for some diurnally driven shower activity through the end of the week. Tuesday night into Wednesday morning a shortwave is progged to dig south across the region bringing in colder air aloft and additional lift to support the maintenance of the above mentioned stronger lake-effect snow band. In fact, soundings show inversion heights increasing overnight to around 10kft, more that sufficient for the production of a deep-convective snow band. 850mb temperatures hovering around -13C will also favor lift through the DGZ, but given the depth of the lift and 20-30 kt winds spanning the convective layer, think the SLRs will be a bit lower compared to our typically super fluffy lake-effect snow. So do have a higher QPF, lower SLR combo which results in an additional 3-5 inches of snow across the Keweenaw Peninsula, stretching southeast towards the Michigamme Highlands/Big Bay, and back over towards Alger/Schoolcraft counties. As for the city of Marquette, right now it looks like this heavier band of lake-effect snow will sit just offshore, given the more westerly gradient winds at the surface. On Wednesday, this stronger lake-effect snow band pushes offshore, but we could see a diurnal flareup of snow showers across the interior with daytime heating. Thursday will feature another shortwave traversing the region and possible diurnal flareup of shower activity. Temperatures will be a bit warmer, so there could be some very light rain that mix in with the snow showers in spots. Overnight lows through mid-week will be on the chilly side across the interior, where single digits will be possible. For the end of the week into next weekend, we look to remain sandwiched between high pressure to the south and a low tracking north of the border in Canada. Thus we will gradually find ourselves under a bout of return flow, which will usher in a gradual warm up back towards normal. Towards the middle/end of next weekend, the surface low north of the border looks to push a cold front down across the region, bringing back chances for precipitation. Ahead of this front, we should see warm and breezy conditions return briefly, followed by another cool down. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 801 PM EDT SUN APR 12 2020 Snow, mdt to hvy at times, will continue thru the night at KIWD/KCMX/KSAW. As a result, LIFR conditions will generally prevail at all terminals. With snowfall heaviest at KSAW, conditions may be blo airfield landing mins for much of the night. Conditions at KCMX may also fall blo land mins at times overnight. Winds will increase during the night and remain strong thru Mon as deepening low pres lifts across the Great Lakes region tonight and into Quebec by Mon evening. All terminals will see gusts to 30-40kt on Tue. Although snow will diminish Mon (ending at KIWD), there is some uncertainty in how long blsn will maintain poor vis. Given the strength of the winds, conditions may remain LIFR and at times blo airfield landing mins at least thru the morning, especially at KCMX/KSAW. KIWD should improve to VFR by mid aftn. By late aftn, improvement to IFR should occur at KCMX and to MVFR at KSAW. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 450 PM EDT SUN APR 12 2020 Winds will continue as winds increase quickly late tonight in response to the deepening low pressure center moving toward eastern Upper Michigan. As the low moves off to the northeast Monday and continues to deepen, expect the strongest winds as colder air is pulled in. Gale warnings west and Storm warnings east remain in effect through Mon evening. By Mon evening, deep low pres will be located s of James Bay. A ridge of high pressure will slowly build in behind this exiting low pressure system on Tuesday as winds gradually diminish below 20 knots by Tuesday evening. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... Winter Storm Warning until 2 AM EDT /1 AM CDT/ Tuesday for MIZ001>003-009-084. Winter Weather Advisory until 8 AM EDT Tuesday for MIZ085. Lakeshore Flood Warning from 8 AM to 8 PM EDT Monday for MIZ001- 003. Lakeshore Flood Warning from 8 AM Monday to 2 AM EDT Tuesday for MIZ005>007. Winter Storm Warning until 8 AM EDT Tuesday for MIZ004>006. Winter Weather Advisory from 6 AM to 8 PM EDT Monday for MIZ007- 014. Winter Storm Warning until 5 PM EDT /4 PM CDT/ Monday for MIZ010- 011-013. Winter Weather Advisory until 4 PM CDT Monday for MIZ012. Lake Superior... Storm Warning from 8 AM Monday to 2 AM EDT Tuesday for LSZ251- 267. Storm Warning until 2 AM EDT Tuesday for LSZ249-250-266. Gale Warning from 5 AM EDT /4 AM CDT/ to 10 PM EDT /9 PM CDT/ Monday for LSZ240>248-263>265. Gale Warning from 5 AM EDT /4 AM CDT/ to 8 PM EDT /7 PM CDT/ Monday for LSZ162. Lake Michigan... Gale Warning from 8 AM to 11 PM EDT Monday for LMZ221-248-250. && $$ UPDATE...Rolfson SHORT TERM...JLB LONG TERM...Ritzman AVIATION...Rolfson MARINE...JLB
Area Forecast Discussion...CORRECTED
National Weather Service Pocatello ID
218 PM MDT Sun Apr 12 2020 .SHORT TERM (Today - Wednesday AM)... Much quieter across eastern Idaho this afternoon compared to 24 hours ago although it`s also quite a bit colder too. Strong cold front has brought much colder temperatures to the region that will stick around for a few days before a gradual warmup begins for the upcoming week. As far as sensible weather is concerned for the next few days, seeing mostly to partly sunny skies across much of the area this afternoon. Some of the hi-res model guidance namely the NAM and HRRR show the potential for some clouds and light snow showers to move southeast out of the central mountains and into portions of the Snake Plain later this afternoon and into the evening. That being said, added a chance of snow showers from Pocatello west through American Falls and over towards Minidoka. If any snow showers did occur in these areas they would likely be very light without too much impact. Overnight temps will be cold, near records in spots with upper teens and lower 20s looking likely. Record low for tomorrow at Pocatello is 17 and the forecast currently sits at 18. Monday will be very similar to today temperature wise although looks like cloud cover will be a touch less in spots. Temps begin to moderate Tuesday back closer to normal for mid-April as the next system looks to approach the region around daybreak Wednesday. McKaughan .LONG TERM (Wednesday - Sunday)... No major changes noted in the long-term portion of the forecast. Our next storm system (a shortwave trough dropping in from the north) remains progged to spread rain and snow showers across the area Wed and Wed night. A few thunderstorms and breezy conditions are also possible Wed afternoon. QPF amounts still don`t look overly impressive with this system, with perhaps a few inches of snow for the mntns. Models linger a few showers into Thurs, but this should be post-trough and post-front, so suspect much of the region will be dry. This is the main feature in the long-term as far as impacts go, and at this time impacts appear fairly limited. Forecast confidence is moderate through Thurs. The GFS/EC/Canadian have trended weaker and further west with the potential coastal low toward the end of the week/next weekend, so odds favor predominantly dry conditions for our forecast area, but model agreement in the details remains low from Fri onward. We made very few deviations from NBM guidance. Temps will gradually warm through the period, from below normal to just above normal by the weekend. - KSmith && .AVIATION... VFR cigs/vsbys are expected across southeast Idaho for the next 24 to 36 hours, with no major aviation impacts. NE winds will remain breezy this afternoon at the Snake Plain terminals but gradually subside into the eve. LLWS is not expected, as winds only gradually increase with height. A shower can`t be ruled out near KSUN or KBYI. NAM time-heights remain insistent that a BKN to OVC mid-level deck will develop for awhile this eve at KPIH/KIDA/KDIJ. It`s possible, but other guidance like the HRRR cig products are not so pessimistic, and we see no obvious source of this inbound on satellite imagery, so we backed this off to SCT in the 18z TAF package and will monitor. Dry conditions expected tonight. - KSmith && .PIH WATCHES/WARNINGS/ADVISORIES... None. && $$
Area Forecast Discussion
National Weather Service Pueblo CO
311 PM MDT Sun Apr 12 2020 .SHORT TERM...(This evening through Monday) Issued at 250 PM MDT Sun Apr 12 2020 Currently... Mostly cloudy to cloudy skies prevail across the plains, while the mtns and valleys had partly cloudy skies. Temperatures have remained quite cold over the lower elevations as temps were only in the 20s and 30s across the plains, while the San Luis Valley has warmed into the mid 50s. Some light radar echoes were still noted generally north of US50 over the plains, but this precip is likely very light. Rest of today and tonight... Main concern is the cold temperatures expected tonight. Guidance continues to forecast lows reaching down into the teens to around 20 over the valleys and plains and negative and positive single digits in the mountains. Any sensitive plants that have germinated may have a hard time with these temps tonight, and any exposed pressurized outside water pipes will likely freeze. Cant rule out some continued light snow continuing along the mtns/plains interface as continued upslope flow is expected through tonight. This is especially true over northern Teller county this evening if the HRRR is correct. This upslope flow will also likely keep cloudiness over the plains with areas of low cigs, especially across El Paso county. Tomorrow... Continued cyclonic flow aloft will continue weak upward vertical motion over the entire region throughout the day. This combined with continued upslope flow will allow for snow showers to continue over the high terrain, and especially on the east slopes of the mtns/plains interface. Likewise, kept highest pops over this region throughout the day tomorrow. Temps should be a few degrees warmer than today, with max readings in the 30s to lower 40s, The SLV should once again be the warmest location with readings in the mid to upper 40s expected. The overall best chance of accumulating snow tomorrow should be Teller and northern El Paso counties where 1 to possibly 3 inches could occur, especially later in the day. .LONG TERM...(Monday night through Sunday) Issued at 250 PM MDT Sun Apr 12 2020 Operational models and ensembles are in better agreement through Friday with differences heading into the weekend. Overall, an active weather pattern is forecast to continue across southern Colorado with periods of Mountain snowfall along with rain and snow over the lower elevations. Monday night through Friday...a longwave trough is forecast to remain over the central states this week with broad northwesterly flow across Colorado. Several upper level disturbances embedded in the flow will move across the region through the end of the week. A quick moving upper wave will drop south across Colorado Monday night into Tuesday morning. Models are in good agreement with a decent shot of widespread snowfall across the area. Given the cold temperatures in place, and the overnight arrival, snow is expected across all of southern Colorado as the wave passes. Mountain areas, and locations favored by northeasterly upslope flow will likely see the greatest potential for accumulating snow. Totals over the mountains of 1 to 4 inches are expected with locally higher amounts possible. Less than an inch is expected over the Plains. Models in good agreement with snow coming to an end late Monday night into Tuesday morning, from northwest to southeast. For Tuesday and Wednesday, northwesterly flow will favor orographic snowfall over the Central Mountains. Minor accumulations are expected. Tuesday will continue to be on the cooler side with highs only reaching into the 40s across the region. By Wednesday, the next upper level disturbance will be approaching the area. Expect an increase in snow showers over the Central Mountains, spread south and east into the Palmer Divide Wednesday night. The upper level disturbance will move across Colorado on Thursday with a strong cold front dropping south across the Plains during the morning. This will bring strong northerly winds to the area and a drop in temperatures. Models in good agreement with Mountain snowfall, while the Plains will be warm enough for rainfall. Snow levels will likely fall to near 6 kft Thursday night before precipitation comes to an end by Friday morning. Friday through Sunday...models begin to diverge heading into the weekend with an upper level low off the California coast. The GFS is fast with the system, bringing it across the region by Saturday. The ECMWF is slower and a bit further north with precipitation holding off until Sunday. For now have low pops across the area this weekend along with warmer temperatures. Mozley && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 250 PM MDT Sun Apr 12 2020 KCOS and KPUB... Unsettled weather to continue over these two taf sites during the next 24 hours as cold cyclonic mid level flow continues over Colorado for the next 24 hours and beyond. Low cigs will be likely through the period as upslope surface flow continues, getting into the MVFR and possibly IFR categories, especially during the nighttime and early morning time periods. Cant rule out some occasional light snow showers, especially KCOS. However any accumulations should be light. KALS VFR next 24 hours. Breezy west winds will be possible tomorrow. && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...HODANISH LONG TERM...MOZLEY AVIATION...HODANISH
Area Forecast Discussion
National Weather Service Springfield MO
628 PM CDT Sun Apr 12 2020 ...00Z AVIATION UPDATE... .SHORT TERM...(This evening through Monday) Issued at 223 PM CDT Sun Apr 12 2020 A strong cold front extends from the KC metro south to near Independence, KS and it will continue to shift east through our forecast area through the early evening hours. Instability hasn`t been very robust and has limited stronger convection. Some breaks in cloud cover has allowed some limited instability over far southwest MO with temperatures in the mid 60s. HRRR may be overdone, but latest runs do show some mlcape around 1000 j/kg close to the MO/AR ahead of the front as it moves through. Marginal hail/wind risk is possible with the best potential south of MO Hwy 60 through mid evening along/ahead of the front. Much colder temperatures and strong winds will move in behind the front, and this is well advertised with a wind advisory and freeze warning. No changes are planned. Winds will diminish late tonight into Monday with dry and very cool conditions. We will probably need another couple of nights of freeze/frost headlines this week but will take those one day at a time. A thick overcast from a broad area of isentropic upglide ahead of shortwave approaching from the west should keep temperatures from free falling Monday night, but we may see some sprinkles/flurries over the sw cwfa. .LONG TERM...(Tuesday through Sunday) Issued at 223 PM CDT Sun Apr 12 2020 Below normal temperatures are expected through midweek. A zonal active pattern is expected, but there is quite a bit of spread in sfc frontal positions over the central CONUS. The ops GFS spins up a vigorous sfc low over the area Thu night, but it appears to be an outlier. In general we will see moderating temperatures late in the week with some degree of rain potential but confidence on timing is low given the quick moving system in the zonal flow. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 524 PM CDT Sun Apr 12 2020 Area of showers is currently moving through the sites. Thunder chances will likely remain closer to BBG. Ceilings will drop to IFR and winds will switch to the northwest with gusts of 35-40kts likely. Visibilities will also briefly drop to 2-5 miles in the rain. Winds will remain gusty through the night. Conditions will improve back to MVFR by early Monday morning. && .SGF WATCHES/WARNINGS/ADVISORIES... MO...Wind Advisory until 7 AM CDT Monday for MOZ055>058-066>071- 077>083-088>098-101>106. Freeze Warning from 1 AM to 10 AM CDT Monday for MOZ055>058- 066>071-077>083-088>096-101>105. KS...Wind Advisory until 7 AM CDT Monday for KSZ073-097-101. Freeze Warning from 1 AM to 10 AM CDT Monday for KSZ073-097-101. && $$ SHORT TERM...DSA LONG TERM...DSA AVIATION...Burchfield
Area Forecast Discussion
National Weather Service Las Vegas NV
503 PM PDT Sun Apr 12 2020 .SYNOPSIS...Waning shower and thunderstorm chances tonight becoming mostly clear and dry by tomorrow morning. Dry weather is expected Tuesday through Thursday with temperatures below normal Monday and Tuesday increasing Wednesday and Thursday. Another system could bring more shower activity and slightly cooler temperatures to the area on Friday before warm and dry weather returns for the weekend. && .EVENING UPDATE... Majority of the showers and storms this evening have decreased in strength as instability decreases across the CWA. Afternoon convection just the help of the higher terrain to tap into an otherwise impressive environment characterized by over 1000 j/kg of CAPE and 30-40 kts of effective shear. The HRRR has done quite an outstanding job depicting this evolution since yesterday which prompted the increase in PoPs and thunder mention across the CWA yesterday. Latest trends show the remaining activity quickly eroding as it pushes southeast and have waned PoPs/QPF through 12Z to reflect the latest HRRR trends. Still a low chance for minor flooding where locations have already seen 0.5" or great across southern Nevada and the Colorado River Valley. Between 12-18Z tomorrow morning, skies will clear up quickly and PoPs will drop to below mentionable levels to begin the upcoming week of dry and mild conditions. .SHORT TERM...tonight and Monday. Shower and thunderstorm chances continue this evening across portions of Mohave, Clark, Inyo, southern Nye and northeast San Bernardino counties with chances primarily east of Las Vegas overnight including the Colorado River Valley and Mohave County. Windy conditions in the Western Mojave Desert early in the evening is expected to decrease overnight. On Monday, shower chances linger across portions of Mohave County with dry conditions and below normal temperatures. Winds are forecast to increase late in the afternoon Monday in northern Inyo County, across the Western Mojave Desert and across the southern Great Basin. Tuesday through Saturday...models have a dry northwest flow over the area Tuesday and Wednesday which then transitions to westerly ahead of an approaching upstream system moving south parallel to the coastline. This system could bring another round of showers to the area on Friday. Temperatures remain on the cool side of normal Tuesday before warm back to normal or above Wednesday and Thursday. Next weekend looks dry and mild with above normal temperatures. However, there is some uncertainty with that and this lowers forecast confidence. $$ .AVIATION...For McCarran...Lingering showers will be possible through 05Z this evening, but the chances of thunder at this point is minimal. Winds have become variable across the valley with gusts to about 20 kts at times. Ceilings should increase substantially after 06Z with the remaining concern for Monday being whether northerly winds will be strong enough to influence runway configuration. For the rest of southern Nevada, northwest Arizona and southeast California...Continued potential for -TSRA and another several hours of SHRA potential for KIFP/KEED through 08Z. Ceilings aoa 5-6kft can be expected with brief visibility reductions as heavier showers move through the terminals. After 08Z, expecting winds to be mostly light with improving ceilings through Monday morning. Elsewhere, rain should be over for KBIH/KVGT/KHND with improvement expected through the overnight hours. KDAG winds are expected to increase and become gusty through tomorrow morning. && .SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report any significant weather or impacts according to standard operating procedures. && $$ DISCUSSION...Salmen AVIATION...Gorelow For more forecast information...see us on our webpage: or follow us on Facebook and Twitter