Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/22/17

Area Forecast Discussion
National Weather Service Columbia SC
723 PM EDT Tue Mar 21 2017 .SYNOPSIS... A cold front approaching from the north will slowly cross the forecast area overnight. Numerous showers and thunderstorms are expected head of the front. Very warm temperatures this afternoon will be followed by cooler temperatures behind the front. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... Regional radars currently showing strong thunderstorms in the upstate of both SC and GA this evening. This activity has been relatively stationary, with a the storms having difficulty pushing eastward into a capping inversion currently over central portions of SC. This inversion will weaken as the evening progresses, and the activity is expected to eventually begin tracking eastward. This will be in advance of a MCS that is moving into eastern TN this evening, and this MCS is expected to rapidly push eastward across northern GA and into northern/central SC, and eastern GS by midnight. As this MCS catches up with the current convection across the upstate, expect to see the entire complex push east/southeastward through much of the cwa. This continues to be supported by the latest hrrr guidance. The main threats will be damaging winds, large hail, and even some heavy rainfall in the slower moving, possible training, storms. The high-resolution models have trended slower with the timing. The latest HRRR is still indicating some isolated to scattered convection possible between 8 pm and 11 pm, the the most widespread shower and thunderstorm coverage by midnight. The more intense convection shifts east of the area by 200 am, with mainly some stratiform rainfall in its wake. The front should shift south of the area after 400 am. There may be lingering showers in the area. Followed the guidance consensus for the temperature forecast overnight. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/... The cold front will be moving south of the area Wednesday morning with high pressure centered over the western Great Lakes region building in behind it. Clouds are expected to linger, but precipitation should be south of the area so have lowered pops. Highs on Wednesday are forecast in the middle 60s to lower 70s. The center of high pressure will move into the Delmarva region on Thursday and ridge into the forecast area from the northeast. Models have trended drier with pops on Thursday. Extensive cloud cover should result in temperatures well below normal on Thursday, but confidence low regarding exactly how low temperatures will be given model differences. && .LONG TERM /FRIDAY THROUGH TUESDAY/... An upper ridge will be centered over the southeastern US on Friday and will push off the coast on Saturday as an upper trough over the Plains lifts northeastward. Surface high pressure will be off the coast on Friday and will continue to ridge into the area from the northeast with dry weather expected. Temperatures will rebound on Friday back into the middle 60s to lower 70s under the influence of the ridge. A low pressure system over the southern Plains will shift northeastward toward the southern Great Lakes region on Saturday and bring a front into the area on Sunday. The frontal boundary will linger in the area on Monday and remain near the area on Tuesday. Temperatures over the weekend and into Tuesday above normal. && .AVIATION /00Z TUESDAY THROUGH SUNDAY/... VFR conditions will continue for the next couple hours, but then MVFR ceilings are likely as strong thunderstorms move into the area. There will also be periods of IFR conditions in heavy rain, but too difficult to time. Storms could develop over KAGS and KDNL as early as 01Z. Upstream convection is expected to move over CAE and CUB around 02Z, and then OGB. Timing is based on HRRR, but these storms have so far been moving very slowly, and arrival could actually be later. Strong heating ahead of the front and very cold air aloft support the potential for damaging wind and large hail with any thunderstorms. There should be a diminished threat of severe weather after 05Z because of previous convection and nocturnal cooling. The front should shift south of the area after 09Z, and skies should clear by 22/21Z. Winds will generally be 5 to 10 kts with gusts up to 20 kts, SW then veering NW, and the NE behind the front. EXTENDED AVIATION OUTLOOK...There may be restrictions mainly in the early morning hours during the outlook period associated with a moist onshore flow. && .CAE WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. && $$
Area Forecast Discussion
National Weather Service Cheyenne WY
831 PM MDT Tue Mar 21 2017 .UPDATE... Issued at 831 PM MDT Tue Mar 21 2017 The forecast overall is in good shape for the rest of tonight. Just added in some fog for the southern Laramie Range, eastern foothills, and Cheyenne proper tonight within moist south- southeast flow up the Cheyenne Ridge and Laramie Range. This includes I-80 from Cheyenne to the Summit, and I-25 from the CO border to Chugwater. HRRR guidance has been consistent showing fog in this area for tonight, and agree with this assessment as south-southeasterly winds favor stratus and fog development here. Expect visibility to be reduced to a mile or less in the fog. && .SHORT TERM...(This evening through Thursday night) Issued at 250 PM MDT Tue Mar 21 2017 Forecast challenges deal with a potential winter storm Thursday night into Friday. Currently...Stationary frontal boundary lays over southeast Wyoming this afternoon. Radar showing fairly widespread shower activity along the front that is moving northeast at 30 MPH. Strong low pressure seen on water vapor imagery still off the Oregon coast. For tonight, upper shortwave tracking northeast lifts stationary front to the northeast to our northern counties. Short range HRRR guidance showing showers lifting to the northeast with drier conditions across the south. A pretty warm day Wednesday as westerly winds predominate the area. 700mb temperatures climb to +6C with some downsloping off the Laramie Range. Looking at highs upper 60s/low 70s for areas east of the Laramie Range with low 60s west. Thursday is going to be unsettled as the Pacific low moves into western Colorado. Widespread upper level diffluence over south central Wyoming with precip beginning Thursday afternoon across Carbon and Albany Counties. 700mb temperatures still above freezing initially Thursday afternoon, but as the low tracks into eastern Colorado, temperatures fall quite quickly. By 06Z Friday, 700mb temperatures down to -5C across Carbon County. Anticipate rain changing over to snow quite quickly Thursday night. Strong northeasterly winds at 700mb. ECMWF showing 55-60kts over the Laramie Range. GFS 700mb winds 35-40kts. So looks like we should be getting some strong winds with the snow as well. .LONG TERM...(Friday through Tuesday) Issued at 250 PM MDT Tue Mar 21 2017 Generally mild and rather unsettled weather anticipated across the CWA this period in a progressive flow pattern. Pcpn will end slowly across the southeast part of the CWA Friday as a vertically stacked low drifts slowly east across the Kansas/Oklahoma area. Windy conditions Friday over the plains but easing by late in the day. Dry weather Friday night into Saturday as a short ridge moves by then the next shortwave will move across later Saturday into Sunday bringing another round of rain and higher-elevation snow showers. Brief lull again late Sunday into Monday then the next in the series of shortwaves arrives for late Monday into Tuesday returning rain and snow to the fcst then. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 622 PM MDT Tue Mar 21 2017 Showers will continue across the area through the early overnight period, but minimal impacts are expected from this activity. For much of the area, winds will be out of the east to southeast gusting 20-25kts or so this evening, switching to a more southerly component with gusts increasing to 30kts tonight. The exception will be in southern Carbon County where winds will remain out of the southwest. Moderate winds and moist upslope flow look to produce low stratus and areas of fog at KCYS tonight according to the latest guidance. Added IFR cigs/vsbys after 07Z tonight, but there is a chance conditions could drop below IFR at times through early Wednesday morning. KSNY could have a similar stratus/fog problem, but right now confidence is highest for only MVFR cigs. Will reassess for the 06Z TAF issuance. VFR is expected elsewhere, but will watch conditions closely this evening for possible expansion of MVFR/IFR across the plains. Once cigs lift Wednesday morning, conditions should remain mostly dry and breezy through the day. && .FIRE WEATHER... Issued at 250 PM MDT Tue Mar 21 2017 A stalled front over southeast Wyoming interacting with upper level disturbances will produce scattered showers and isolated thunderstorms this afternoon along and west of Interstate 25. The front will shift east into the plains Wednesday as west to southwest winds increase ahead of a stronger Pacific low pressure system. This low will track east across the central Rockies and plains Thursday through Friday bringing widespread rain and snow to the districts. Minimum relative humidities the next few days will range from 20 to 30 percent, with fair to good nighttime recoveries. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...None. NE...None. && $$ UPDATE...RJM SHORT TERM...GCC/DEL LONG TERM...RE AVIATION...RJM FIRE WEATHER...GCC
Area Forecast Discussion
National Weather Service Quad Cities IA IL
948 PM CDT Tue Mar 21 2017 .UPDATE... Issued at 930 PM CDT Tue Mar 21 2017 Have updated to increase sky cover overnight and adjust mins up a bit especially east central IA into northwest IL. Lake Mi stratus propagating SSW at near 20 kts in wake of pronounced wind shift. NAM and RAP mslp and surface wind fields bring this lake enhanced boundary into far eastern cwa prior to 05z then toward Mississippi river overnight before washing out in developing broad northeasterly low level flow. Attendant to this boundary and evolving broad northeast flow at 20-25 kts in 1-3kft agl layer will be lake enhanced stratus. NAM/RAP low level rh progs have a decent handle on the lake stratus and followed for sky grids going with pt-mocldy developing overnight across NW IL into portions of eastern IA especially through the Hwy 30 to I-80 corridors... possibly reaching near IOW/CID toward daybreak. As a result of this increase in cloud cover I have also nudged up lows a bit. SW cwa will continue to see sct-bkn high cloudiness at times overnight. Overall, expect skies to become partly to mostly cloudy across much of the cwa. Updated grids/PFM/ZFP have been sent. && .SYNOPSIS... Issued at 307 PM CDT Tue Mar 21 2017 As expected the mid-level frontogenetic band of rain, triggered by a short wave moving quickly across Iowa, has continued to diminish and was pushing rather quickly to the southeast. The HRRR model indicated the rain should exit the dvn cwa by late this afternoon (4 pm). && .SHORT TERM...(This Evening through Wednesday) ISSUED AT 307 PM CDT Tue Mar 21 2017 Forecast focus on dry but chilly weather in the short term. Tonight: Subsidence in the wake of the short wave pushing off to our east should bring clear to partly cloudy skies for most of the night. Canadian high pressure (1040 mb)centered in Manitoba will slide to Lake Superior by sunrise. This will funnel cold air into the area on north to northeast winds. Minimum temperatures will be in the 20s. Wednesday: As the high pressure pushes towards the eastern Great Lakes region, winds will veer to the east to southeast. Mid/high level clouds should increase as gradually strengthening mid-level warm air advection develops on the return flow. The thickening cloud deck should keep temperatures on the chilly side for late March, with highs in the lower to mid 40s. This would be about 10 degrees cooler than normal. .LONG TERM...(Wednesday Night through Tuesday) ISSUED AT 307 PM CDT Tue Mar 21 2017 The weather pattern will be turning very active the second half of the week across the Midwest and is expected to continue through the end of the month. Some of the extratropical cyclones that develop across the CONUS will have the potential to be strong. Water vapor imagery shows numerous storms across the Pacific Ocean all the way into eastern Asia. That being said, the active pattern does not mean there will be a continuous rain. There will be periods of dry weather. However, precipitation does have the potential to average above normal through the end of the month. Quiet and dry conditions will be seen across the area Wednesday night as high pressure moves into the eastern Great Lakes. Attention then turns to the first rain event for Thursday. The strength of the high and depth of the dry air will dictate when precipitation develops and what it will initially be on Thursday. The current model consensus has slight chance to chance pops west of a Galena to Kewanee, IL line Thursday morning. However, this will likely be the areal coverage by the noon hour on Thursday. The entire area may start out dry at sunrise Thursday. Profiles of the atmosphere do show a layer of dry air at the surface. This dry air may be just enough to allow an initial period of sleet before quickly changing to a rain/snow mix and then all rain as the dry layer saturates. Thursday afternoon there should be an area of rain moving from south to north across the area as the stronger forcing acts upon an elevated front moving through the area. Thursday night the better forcing and elevated front move north of the area. The increasingly moist and unstable air should allow the precipitation to be showers with some elevated thunderstorms north of I-80. Mainly dry conditions should be seen across the area Friday morning while the next storm system moves out of the Plains. By Friday afternoon scattered showers along with some thunderstorms are expected to develop with the better coverage west of the Mississippi. Temperatures look to be well above normal. Friday night on... While the weather pattern is projected to remain very active, the models continue to vary considerably from run to run on the overall track and details regarding each storm system. Dprog/DT of the model runs is suggesting a southward shift in the storm track Friday night into Saturday. Friday night and Saturday the model consensus has likely to categorical pops. While the models disagree on the overall track and details, it is starting to look like a widespread general rain event with some embedded thunderstorms. Temperatures should generally average above normal. Saturday night into Sunday the model consensus has chance to likely pops with the next system moving through the Midwest. The model solutions are diverging on their respective solutions regarding how quickly the system will exit the area or where it will track. Right now the precipitation type looks to be all rain. There may or may not be some embedded thunderstorms. Sunday night the model consensus has slight chance to chance pops mainly west of an Independence, IA to Macomb, IL line for the next storm system. Depending upon on how quickly this system arrives, the possibility does exist that Sunday night could be dry. The model consensus has chance to likely pops on Monday and chance pops Monday night for the next in the sequence of storm systems moving through the Midwest. Right now the precipitation type looks to be rain. On Tuesday, the model consensus has mainly dry conditions for the area. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday Evening) ISSUED AT 938 PM CDT Tue Mar 21 2017 Lake enhanced stratus is moving SSW at near 20 kts being handled well by low level NAM/RAP rh progs, and supports MVFR cigs developing into MLI overnight and possibly expanding to the other terminals as well. Will update forecasts as trends play out in the next few hours. Northerly winds around 10 kts will turn easterly overnight and may gust for a brief period of time. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ UPDATE...McClure SYNOPSIS...Haase SHORT TERM...Haase LONG TERM...08 AVIATION...McClure
National Weather Service Eureka CA
353 PM PDT Tue Mar 21 2017 .SYNOPSIS...An upper trough will generate occasional showers tonight through Wednesday. Another storm will impact Northwest California with heavy rain and strong winds Thursday night and Friday. && .DISCUSSION...Convection has been firing up over the coastal waters today in advance of an approaching short-wave trough. A few storms were strong enough to warrant special marine warnings for winds up to 40 kt and possible waterspouts. We have not seen more small scale vortices near shore and over land areas, but the latest HRRR indicates the potential for storms with weak rotating updrafts into early this evening, mainly across SW Humboldt and Del Norte counties. The threat for low topped rotational storms should diminish by late this evening. The leading edge of the cold air boundary probably will not arrive til late tonight. With steep mid level lapse rates and CAPE values below 500J/KG, low topped storms will still be possible into the early morning hours, primarily over the coastal waters. Showers will most likely continue through Wednesday as weak instability persists and NW onshore flow develops after trough passage. The precip will wind down by Wed evening as a shortwave ridge builds over the region. With a colder air mass settling over the region Wed night, frost will be a distinct possibility across interior Mendocino county as skies partially clear out. The latest GFS and NAM12 indicate high boundary layer humidities with virtually no offshore wind flow. It will probably be too foggy with low overcast for frost to be serious concern. This will need to be watched closely. Primary focus Thursday and Friday will shift to an occluding cyclone over the northeastern Pacific. A frontal boundary extending southward from the cyclone is forecast to reach the coast of NW California Thursday night, and then exit east of the area Friday afternoon. High precipitable water values 1 to 3 standard deviations above climatology are forecast along the front. This above normal moisture combined with strong ascent will support locally heavy rain with the frontal passage. In addition, advisory level wind gusts are likely as a 40-60 kt low level jet develops along/ahead of the front. There is very little doubt that the upper elevations of Humboldt and Del Norte counties will see gusts around 50 to 60 mph with this storms if the models are correct. For coastal areas near mean sea level, it is too early to tell for sure how strong winds will get. Later runs from the high resolution mesoscale models may provide better guidance. After the Friday system moves east away from the area, the upper flow regime is forecast to transition to northwesterly. This will lead to periods of shortwave ridging followed by showery upper troughs emanating from the Aleutians region during the Saturday through Tuesday time period. The system slated to arrive Sunday into Sunday night may be slightly colder (lower snow levels) but with less moisture (not as much rain). Shortwave ridging early next week should result in another semi-dry period Mon/Tue with lesser rain chances. && .AVIATION...THIS EVENING, MENTION VICINITY THUNDERSTORM FOR ALL TERMINALS AS THERE WILL BE THREAT OF THUNDERSTORMS IN THE AREA. AS WE LOSE THE DAYTIME HEATING AND THE ASSOCIATED INSTABILITY, THE THREAT OF THUNDERSTORMS WILL DIMINISH LATER THIS EVENING. SHOWERS WILL STILL BE IN THE AREA THROUGH THE LATE EVENING HOURS. BY LATE NIGHT AND EARLY TOMORROW MORNING, SHOWERS WILL DIMINISH AND WE WILL HAVE VICINITY SHOWERS THROUGH WEDNESDAY DAYTIME. DO EXPECT VFR CONDITIONS TO PREVAIL THROUGH THE NEXT 24 HOURS. GUSTY SOUTH WINDS THIS EVENING WILL DIMINISH OVERNIGHT. WINDS WILL BE LIGHT AND FROM THE SOUTHWEST TOMORROW. /RCL && .MARINE...ACTIVE WEATHER PATTERN WILL CONTINUE THROUGH THIS WEEKEND, WITH FLUCTUATING WIND REGIMES AND SEA STAGES. THE FORECAST PERIOD WILL START WITH GUSTY SOUTH WINDS OF 30 TO 35 KT TO THE COASTAL WATERS, WITH COMBINED SEAS AROUND 10 TO 11 FT THIS EVENING. THE WINDS WILL BE SUBSIDING THIS EVENING, ALONG WITH SHOWERS AND ISOLATED THUNDERSTORMS. THE SEAS WILL BE GRADUALLY SUBSIDING TO LESS THAN 8 FEET WEDNESDAY NIGHT. HAVE A GALE WARNING FOR THE NORTHERN OUTER WATER THROUGH THIS EVENING, AND HAVE SMALL CRAFT ADVISORIES FOR THE REST OF THE COASTAL WATERS THROUGH WEDNESDAY NIGHT. WINDS ON WEDNESDAY WILL SWAP TO THE NORTH AS A WEAK TRANSITORY HIGH MOVES THROUGH THE AREA. ON THURSDAY MORNING, WINDS WILL SHIFT TO THE SOUTH AND INCREASE AS A POWERFUL LOW AND ITS ASSOCIATED FRONT MAKES LANDFALL ALONG THE WEST COAST. CONFIDENCE IS INCREASING THAT WE WILL BE SEEING SOME SUSTAINED GALE FORCE WINDS. DO EXPECT COMBINED SEAS TO INCREASE TO 10 TO 14 FEET LATE THURSDAY. WINDS WILL BE DIMINISHING ON FRIDAY BEHIND THE WEATHER FRONT. SEAS WILL REMAIN FAIRLY ELEVATED WITH A PERSISTENT BACKGROUND WESTERLY SWELL AND PERIODS OF WIND DRIVEN WAVES. THE WAVE FORECAST IS FAIRLY COMPLEX FOR THE NEXT WEEK. WAVE MODELS ARE SHOWING POTENTIALLY UP TO 7 DIFFERENT WAVE GROUPS TO IMPACT THE NW CALIFORNIA WATERS. /RCL && .EKA WATCHES/WARNINGS/ADVISORIES... CA...None. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory until 3 AM PDT Wednesday for PZZ450-455-475. Small Craft Advisory until 3 PM PDT this afternoon for PZZ470. Gale Warning until 9 PM PDT this evening for PZZ470. && $$ Visit us at Follow us on Facebook and Twitter at: For forecast zone information see the forecast zone map online:
Area Forecast Discussion
National Weather Service Hastings NE
615 PM CDT Tue Mar 21 2017 .SHORT TERM...(This evening through Wednesday) Issued at 238 PM CDT Tue Mar 21 2017 Biggest issue will be precip chances tonight. Backdoor cold front helping to keep stratus locked in for much of the day in our north/northeast and kept us cooler up there. The HRRR seems to be doing a decent job with the cooler temperatures up there for this afternoon and early evening. As for the upcoming low-amplitude perturbation tonight, numerical models have really backed off on this. Still have low POPs in our west/north, with somewhat higher POPs in our far north, but the main influence of this wave will focus primarily north of the CWA once again. BUFKIT soundings continue to indicate the possibility for sleet in our far north, so I stuck that in there late tonight as a possibility. For Wednesday, Upper level ridging will help ensure a dry day, with seasonable highs in the lower 50s. .LONG TERM...(Wednesday night through Tuesday) Issued at 238 PM CDT Tue Mar 21 2017 Biggest issue will be determining chances and timing of potential precipitation. A succession of waves over the extended will keep chances of precipitation for much of the forecast. At the surface a lee low develops over Colorado as an inverted trough/warm front extends northeast for Thursday. There is a small worry of some hailers in our south during the early morning as MUCAPEs of 500 to 1000 J/kg are not out of the question. Not a lot of effective shear to work with, so not looking for widespread severe weather by any means. We probably will not see a whole lot from this during the day Thursday as we will be on the stable side, but could stand a better chance during the night. It will all depend on where the instability corridor sets up, but it looks like it might wind up being west of the CWA. Thursday could be a stratus filled day if the NAM is right, and we might wind up way cooler than the forecast 60s/70s. Friday trends are for the surface low to be farther south, which will essentially negate our shot at severe weather, and instead, we could see a rain band set up north of the low somewhere on or near us. Saturday may turn out to be more damp as the upper wave becomes more negatively tilted as it departs. Another wave pulling into the Plains will help spawn surface cyclogenesis is likely over the southern Plains by Monday. A blended solution of ensembles and operational models was used in this solution as there is not a lot of agreement with placement/timing. && .AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Wednesday evening) Issued at 611 PM CDT Tue Mar 21 2017 The MVFR ceilings should diminish as the sun goes down this evening, but there are still some mid level clouds moving through the area this evening and into the day tomorrow. && .GID WATCHES/WARNINGS/ADVISORIES... NE...None. KS...None. && $$ SHORT TERM...Heinlein LONG TERM...Heinlein AVIATION...JCB
Area Forecast Discussion
National Weather Service Gray ME
1038 PM EDT Tue Mar 21 2017 .SYNOPSIS... An arctic front will push south through the region late tonight, and produce a very cold and windy Wednesday. High pressure will build in from the west Wednesday night through Thursday. High pressure will shift east Thursday night. A warm front will approach from the southwest Friday followed by a cold front Friday night. High pressure will build south from Canada Saturday through Sunday. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... 1040 PM Update...Just a few minor adjustments to the forecast based on latest trends in surface obs as well as satellite and radar data. 745 PM Update...Little change to the going forecast. Occasional snow continues in the higher terrain of the western ME Mountains and the Whites. Scattered rain/snow grain showers are also occurring from time to time further south. An arctic cold front continues to approach from the NW is expected to sweep across the region later tonight. A few squalls remain possible with the front. 6 PM Update...Have updated the forecast mainly in the PoP/Wx and temperature departments. Loosely organized snow banding is taking place across the western ME mountains, some of which is heavy based on some web cams. The HRRR continues a pretty narrow band of potentially mod-hvy snow through the evening, particularly across higher elevations of Franklin County. Have increased snow amounts to a few inches there. Otherwise, an arctic front is expected to move through later tonight - perhaps allowing for a band of snow squalls (mainly in the mountains). Previously... Some mid lvl WAA associated with weak low pressure form ahead of sfc cold front setting off a cluster of showers of rain and snow moving across nrn zones at this times. This should shift E in the next couple of hours, with a bit of a dry period. in the hours around sunset. The sharp edge to the arctic air will move through from late evening thru the pre-dawn. Scattered snow showers are a good bet in the mountains, with some squalls possible across the nrn zones. Models are stingy with bringing much in the way of snow showers with the front into srn half of NH or coastal plain of ME, but could see a few isolated SHSN after midnight in these areas. Temps will drop slowly through the evening, but once the cold front moves through the will begin to fall off quickly late with lows 15-20 in the N and around 30 in the south. Winds will also pick up fairly quickly behind the front, but strongest winds will be during the day Wednesday. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/... Strong CAA and gusty NW winds behind the front will allow for temps for temps drop through out the day, with highs early the day. Winds will pick up during the morning probably to around 20 mph with gusts around 40 mph at times, especially in the afternoon. Models keep gusts below wind adv criteria, but it gets close, so will have to watch for potential advisory in some spots. Temps will fall thru the teens and 20s during the afternoon, with wind chills in the single digits below zero in the mountains, and in the single digits above zero in the south, so it will be quite cold. The March sun will only go so far to counteract the strong CAA. Upslope snow showers will continue through the morning with some accums in the favored upslope areas and on the higher terrain. Winds will be slow diminish Wed evening and temps will continue fall through the night, with wind chills dropping blow zero everywhere and in the -10 to -20 range in the mountains. Lows will bottom out from around zero in the north to around 10 above on the coast and in srn NH. && .LONG TERM /THURSDAY THROUGH TUESDAY/... Broad upper ridge will gradually replace a departing trough Thursday. Surface high pressure building in from the west will produce a mostly sunny day...although temperatures will remain well below normal. Highs will range through the 20s north and lower to mid 30s south. High pressure will shift offshore Thursday night and return flow will begin to bring warmer air back into the region. Expect high clouds to spill over the ridge as a broad area of over-running set up to the west. May see a few flurries or snow showers by daybreak but expect any precip to be light and spotty generally falling off a mid level deck. Lows will range from 5 to 15 north and will range through the teens south. Weak over-running precipitation will continue through the day Friday ahead of a cold front approaching from the west. Will likely see light snow mixing with or changing to rain in southern New Hampshire and southwest Maine as boundary layer temps warm through early afternoon. Models showing some differences in areal extent of this warming with the ECMWF remaining significantly colder. In any case QPF by the end of the day only amounts to a tenth of an inch or less so any impacts will be minimal. Temperatures will be fairly uniform across the region...ranging from the mid 30s north to the mid 40s south. Cold front will swing in from the west Friday night and will push south of the area by Saturday morning. Looking for lingering rain or snow showers to gradually end around midnight as the boundary moves through. looking for partial clearing after midnight as high pressure builds in from the north. Should see temperatures closer to normal overnight with lows from the mid 20s north to the mid 30s south. High pressure building south from Canada will produce a mostly skies Saturday. Not a lot in the way of cold air behind the front as it stalls just southwest of the area so highs top out above normal ranging from the mid 30s to lower 40s north and mid 40s to near 50 south. Models diverge at this point with the ECMWF lifting the front northward ahead of an approaching shortwave while the GFS parks it to the southwest of the area. Have pretty much gone with SB numbers for the remainder of the forecast and confidence quite low for days 6 through 8. && .AVIATION /03Z WEDNESDAY THROUGH SUNDAY/... Short Term...Could see some periods of MVFR overnight in SHSN at KLEB, and especially KHIE, bit otherwise look for MVFR to persist through Wed night. Strong NW wind gusts, to around 35kt at times are expected on Wed, especially in the afternoon. Long Term...VFR Thursday through Thursday night. MVFR/IFR ceilings/vsby Friday and Friday night. VFR Saturday through Sunday. && .MARINE... Short Term...Gales are now effect for all zones Wed into Wed night, as strong NW flow moves in behind a cold front. With very cold air spilling in, have issue fz spray adv for Wed night. Wind should start to diminish a bit late Wed night. Long Term...SCA`s likely Friday. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...Freezing Spray Advisory from 7 PM Wednesday to 10 AM EDT Thursday for ANZ150>154. Gale Warning from 8 AM Wednesday to midnight EDT Wednesday night for ANZ153. Gale Warning from 8 AM Wednesday to 8 AM EDT Thursday for ANZ150>152-154. && $$ NEAR TERM...Ekster
Area Forecast Discussion
National Weather Service Memphis TN
1012 PM CDT Tue Mar 21 2017 .UPDATE... A cold front has pushed through the Mid-South this evening. As a result, temperatures have dropped into the 50s and 60s behind the front. Even though the front has passed, chances for showers and thunderstorms will continue into the overnight hours as a shortwave moves through the region. Current KNQA radar shows a band of showers with a few embedded thunderstorms moving into Northeast Arkansas, the Missouri Bootheel, and Northwest Tennessee at this time. The latest HRRR brings this band south to the Mississippi/Tennessee border by 6-7 AM CDT. Will update to go likely POPS for areas north of a Memphis to Jackson line. Otherwise, rest of forecast looks good. Update will be out shortly. KRM && .DISCUSSION... /issued 338 PM CDT Tue Mar 21 2017/ Conditions supportive of severe weather near the Tennessee River are quickly diminishing. Only showers and an isolated thunderstorm or two are expected across the remainder of the Midsouth overnight. We will likely cancel the watch within the hour. Tomorrow we will be situated on the far eastern edge of a broad ridge centered over the plains and on the Southern edge of high pressure centered over the Great Lakes. Isolated showers can`t be ruled out...but most areas will remain cloudy and dry. No significant rain chances will return to the Midsouth until late Friday as the ridge over the Plains strengthens and shifts slowly East. Temperatures tomorrow will be significantly cooler with abundant cloud cover. Highs will be mostly in the 50s although the warmest portions of North Mississippi may approach the middle 60s. Temperatures will rebound quickly back into the middle 60s to middle 70s Thursday. Southerly flow will return Friday boosting temperatures back into the middle 70s across most of the region. The ridge axis that will keep us dry for the next few days will shift across the Mississippi River early Friday resulting in Southwest flow over the Midsouth. Over the weekend into next week, we will be under progressive flow. Two dynamic systems are expected to impact the Midsouth, first Late Friday into Saturday morning and again Sunday night into early Monday. Each of these systems could produce strong to severe thunderstorms although exact details would just be a guess. Both systems do appear they will have much more dynamic energy to work with than todays storm...and temperatures should be back in the 70s suggesting that thermodynamic support should be adequate. A shortwave ridge oriented from Northwest to Southeast will shift across the Midsouth Sunday between storm systems. 30 && .AVIATION... A cold front located is moving through North MS. VFR conds prevail with ocnl MVFR cigs behind the front tonight. Later tonight sct shras will move across the Mid-South continuing into early Thu. Mainly VFR conds expected Thursday. NE winds at 10-12 kts through the period. SJM && && .MEG WATCHES/WARNINGS/ADVISORIES... AR...None. MO...None. MS...None. TN...None. && $$
Area Forecast Discussion
National Weather Service Newport/Morehead City NC
950 PM EDT Tue Mar 21 2017 .SYNOPSIS... Low pressure will move through the area tonight. The low will move well offshore Wednesday as high pressure builds in from the northwest. The high will continue to build over the area through Thursday then slide offshore Friday. An area of low pressure will approach the area late this weekend. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... As of 945 PM Tue... Active MCS continues to roll across southern NC and most of SC at this hour. This system has produced large hail in the Charlotte area and especially in upstate SC. Latest GOES-R satellite imagery showing the coldest cloud tops are over SC with only a couple of strong storm cells over southern NC. Think most of the strong storms will remain south of our CWA...but do expect the possibility of a heavy downpour and a few rumbles of thunder toward morning along with a few wind gusts. Further north across the coastal plains...latest HRRR shows widespread showers and have high chance PoPs far northwest to likely over most of the remainder of the CWA overnight. Highs reached 80 degrees or better at several locations in the southwestern CWA this afternoon. The cold front is moving very slowly and continues on roughly on a HSE-PGV line and temperatures have already dropped into the 50s at MQI and HSE. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/... As of 330 PM Tue... Clouds and even a few showers will linger into mid morning Wednesday especially over the coastal counties. Drier air will win out by midday, with a clearing sky by afternoon. Temps will be much cooler, with a northeast flow dragging in cooler weather. Highs by afternoon will still be near 60, but this will be a good 20 degrees cooler than today, especially inland. The pressure gradient between high pressure over the upper midwest and the low off shore will also lead to breezy weather, with gusts over 20 mph likely from mid morning on. && .LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/... As of 245 PM Tue...Arctic high pressure will build into the region Wednesday night and Thursday bringing below normal temperatures with much of the area dropping below freezing Thursday and Friday mornings. The high will move offshore Friday bringing moderating temperatures into the weekend. A frontal system will approach from the west late in the weekend bringing an increased chance of showers. Wednesday night through Thursday night...Arctic high pressure builds into the region Wed night through Thu night bringing temperatures several degrees below normal and the threat of below freezing temperatures across much of the area each morning. Skies will be mainly clear through the period but could see increased mid/high clouds late Wed night and early Thu as a fast moving and weak shortwave moves through NW flow aloft. Lows Thu morning expected in the upper 20s/lower 30s inland to low to mid 30s along the coast. Highs Thursday will be in the low to mid 50s well inland and southern areas but remain in the mid to upper 40s NE sections and the OBX. Brisk northerly winds will continue Thursday and wind chills will keep it feeling more like the mid 30s to mid 40s across much of the area. Cold again Thu night/Fri morning with temperatures near freezing inland and 35 to 40 along the coast. Friday through Tuesday...The high moves offshore Fri bringing moderating temperatures through the weekend and early next week. Models trending drier for Sat and think Fri, Sat, and likely Sat night will remain dry...though could see increasing shower chances off the coast near the Gulf Stream Sat. Models show a vertically stacked low pressure system tracking across the Ohio River Valley Sun, then gradually weakening as it moves off the Mid-Atlantic coast Mon with a trailing cold front sliding across the area. There continues to be a good bit of uncertainty in how this system evolves and impacts ENC with differences between the GFS and ECMWF. Continued to favor the previous forecast and WPC, which leans more towards the ECMWF. Continue chance PoPs Sun and Mon, then tapering to slight chance Mon night and Tue. Will keep sc thunder mention with marginal instability and shear. Temps forecast to warm into the 60s inland Fri, then into the low/mid 70s over the weekend, though coastal areas, especially the OBX will be several degrees cooler in the 60s. && .AVIATION /02Z WEDNESDAY THROUGH SUNDAY/... Short Term /Through 00Z Thursday/... As of 715 PM Tuesday...Not only of changes in the overall trends for this TAF cycle. Line of showers and a few embedded thunderstorms along the outer edges of a strong MCS which will cross most of South Carolina should arrive at the TAF sites between 04z and 08z. This line of showers will cross the CWA and move offshore early Wednesday morning. Currently forecasting some MVFR ceilings to coincide with the highest precipitation threat from 07z to about 12z. A return to VFR is expected after 12Z Wednesday but a mid deck will linger through late morning before total clearing from the north. Light northeast winds tonight at less than 10 kts will increase Wednesday, with northeast winds 10 to 20 kts common all terminals. Long Term /Wed night through Sunday/... As of 245 PM Tue...Pred VFR conditions expected Wed night through Sat...though cannot rule out patchy early morning fog late in the week as temps/dewpoints moderate. Sub-VFR conditions possible Sunday as a frontal system approaches the region with scattered showers developing. && .MARINE... Short Term.../through Wednesday/... As of 950 PM Tuesday...Frontal boundary moving slowly south currently on a Hatteras to Greenville line. Winds are generally light NE north of Cape Hatteras and SW to the south at speeds of 10 knots or less. Seas are in the 3-5 foot range currently. No major changes to forecast. A Gale Warning is in effect for Wednesday/Wednesday evening for all of the coastal waters outside of the far northern waters, along with the Pamlico Sound. A small craft advisory has been issued for the far northern coastal waters from Oregon Inlet north, along with Albemarle sound and Alligator River. Winds will be NE to NNE through the period, 25 to 35 kts in the gale warning and 25 to 30 (with occasional gusts to 35 kts in the advisory area). In fact over the far end of the Albemarle sound and the southeast part of our northern waters, brief gales are possible but not long enough in duration to include them in the warning. Waves will run between 5 and 10 feet. Long Term /Wednesday night through Sunday/... As of 245 PM Tue...Gusty north winds 20-25 kt Wed evening will slowly diminish late Wed night and Thu to around 10-20 kt by Thu afternoon. Light winds expected Fri as the high shifts off the coast, with S/SW winds re-developing and increasing to 10-15 kt Fri night though Sunday. Seas 6-10 feet Wed evening, gradually subsiding and should drop below 6 feet by late Thu afternoon and early evening. Fri though Sun expect seas pred 2-4 feet. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...None. MARINE...Gale Warning from 9 AM to 8 PM EDT Wednesday for AMZ135. Small Craft Advisory from 9 AM Wednesday to 2 AM EDT Thursday for AMZ130-131. Gale Warning from 7 AM to 9 PM EDT Wednesday for AMZ152-154- 156-158. Small Craft Advisory from 7 AM Wednesday to noon EDT Thursday for AMZ150. && $$ SYNOPSIS...EH NEAR TERM...CTC SHORT TERM...EH LONG TERM...RSB/CQD AVIATION...CTC/EH/CQD MARINE...CTC/EH/CQD
Area Forecast Discussion
National Weather Service Melbourne FL
940 PM EDT Tue Mar 21 2017 .DISCUSSION... Only change to the forecast was to show an increase cloud cover late tonight across the north as increasing westerly flow above the boundary layer combined with some cyclonic flow may produce some stratus and patchy fog spreading E/SE from north FL and the Gulf coast. Otherwise, winds and temps look good for the overnight. Overnight-Wednesday...(previous) High pressure ridge over the southern CWA will slip southward and weaken ahead of increasing westerly pre-frontal flow ahead of a weak back door frontal boundary, which the models continue to accelerate faster toward/into the northern CWA compared to previous runs. 12Z guidance is now showing increasing NE winds leaking out ahead of the boundary/main surge, reaching the NE CWA and adjacent central coastal areas between 21Z-00Z, with any showers holding off over water/land until after 00Z, though it`s likely they`ll be knocking on the door of the CWA/MAOR not too long after. MOS temps for tonight are cooler across the southern CWA (L-M50s) compared to the north (U50s), which fits scenario of a retreating surface ridge over the southern CWA, along with weak return (WSW-W) boundary layer flow on its north side. Wednesday maxes will reach L80s along the coast ahead of an afternoon ECSB, and M80s inland. && .AVIATION... Mainly VFR/SKC. MOS guidance, HRRR and local WRF are indicating some stratus and patchy fog late tonight across the north. Have introduced a TEMPO for IFR CIGs at LEE with MVFR VSBYs. This may need to be expanded eastward to include MCO/SFB/DAB. && .MARINE... Tonight-Wed...(Modified) Slow decay in NE swell will continue overnight into Wednesday, with a continued lack of significant wind chop, given the developing offshore flow. Increasing northerly flow will spread into the Volusia county waters late Wed behind a back door front. Seas 3-5FT tonight will subside to 3-4FT around sunrise, and 2-3FT late Wednesday afternoon. && .FIRE WEATHER...(previous) Wed...Marginally low min RH values in the L30s expected south of Lake Kissimmee and Melbourne on Wednesday afternoon, inland away from the coast. However, lack of sufficiently high ERC values and/or sustained windspeeds precludes any potential RFW issuance. Thu/Sun...Brisk onshore surface/transport flow thru Sat will diminish on Sun as high pres builds over the W Atlc and gradually erodes. The extended pd of onshore flow will all but ensure min RH values remain well abv critical lvls thru the upcoming weekend. && .PRELIMINARY POINT TEMPS/POPS... DAB 58 81 64 74 / 0 10 40 40 MCO 59 85 63 78 / 0 0 20 40 MLB 58 82 65 75 / 0 0 40 60 VRB 55 82 65 76 / 0 0 40 60 LEE 60 84 61 78 / 0 0 20 40 SFB 59 84 63 77 / 0 0 30 40 ORL 60 85 62 78 / 0 0 20 40 FPR 54 82 64 76 / 0 0 40 60 && .MLB WATCHES/WARNINGS/ADVISORIES... FL...None. AM...None. && $$ Kelly/Sedlock
Area Forecast Discussion
National Weather Service Pocatello ID
156 PM MDT Tue Mar 21 2017 .SHORT TERM...Tonight through Friday. A surface low will push through Idaho tonight. It will spread rain and very high elevation snow showers through all of southeast Idaho this evening. Snow levels start at 9000 feet then drop to 6 to 7 thousand feet by morning. Have 1 to 3 inches above 8000 feet in grids through Thursday morning. Most precipitation will shift to southern and eastern highlands Wednesday night through Thursday. An upper ridge should bring dry conditions Thursday night and through Friday morning. Another system will likely spread precipiation back into the central mountains Friday afternoon. Will have much cooler temperatures on Wednesday and Thursday with warming to again well above normal ahead of the next system on Friday. GK .LONG TERM...Friday night through Tuesday. Progressive spring pattern continues with multiple shortwave troughs passing through East Idaho. Best chance at DRY weather occurs Sunday otherwise precipitation expected nearly every period. Multiple cold fronts gradually drop temperatures through the period toward climatic normals, mainly Sunday and again Monday night. Still do not expect snow levels to reach valley floors, but moderate accumulations mainly above 6500 feet could be possible. DMH && .HYDROLOGY...Snow melt runoff continuing to impact East Idaho. Water still running in many places, and all advisories have been continued. Portneuf River remains above flood stage with warning in place. Latest forecast crests river just at moderate stage with secondary crest just above moderate stage this weekend. Bear River continues to climb but forecasts keep river just below flood stage so have continued watch. Snake River at Blackfoot just above action stage through the week without a significant climb. Opted to continue broad river statement managing overall conditions across the region. Only other change today was to remove portions of the flood watch in the Snake Plain where snow cover has dissipated. DMH && .AVIATION...VFR and breezy conditions at many locations this afternoon. So far weak showers trying to develop near KSUN and KDIJ otherwise do not expect precipitation to develop until later this evening. Models again struggling with timing and placement of precipitation but consensus still points to 00Z-09Z being the focus across the region. HRRR also developing what appears to be a consolidated outflow associated with the main batch of convection. This could bring the winds back into the 15-20kt sustained range briefly as the convection passes through. DMH && .PIH WATCHES/WARNINGS/ADVISORIES... Flood Watch through Thursday morning for IDZ017>019-021>025-031- 032. && $$
Area Forecast Discussion
National Weather Service Raleigh NC
935 PM EDT Tue Mar 21 2017 .SYNOPSIS... A cold front will push slowly southward through the area tonight. Cool high pressure will build into the region from the north Wednesday through Thursday night, then shift off the East Coast on Friday. && .NEAR TERM /Through Tonight/... As of 935 PM Tuesday... Severe storms just to our SW, along the southward-pushing surface frontal zone, are knocking on our CWA`s door, moving into more favorable deep layer shear, but the thermodynamic environment is much less favorable in our area for maintenance of these cells as they ease into our area and leave behind the high mid level lapse rates (7.5-8.0 C/km over the W Carolinas). We`ll continue to see showers and storms cross our SW and extreme southern sections through the overnight hours as the MCV tracks SE across SC and far southern NC, supported by strong upper divergence in the right entrance region of a small 120+ kt jet to our north. The initially moderate CAPE over our SW sections and to the S and SW will steadily dwindle and shift further southward over the next few hours according to recent RAP runs, as the surface mass convergence zone drops southward toward the NC/SC border. We may still see some lighter showers spread up toward the Triangle and further NE over the Coastal Plain beneath the upper divergence maximum, ahead of the passing 850 mb trough. Will maintain likely pops overnight, with an isolated strong storm or two possible just for the next couple of hours, trending to low chance pops over the rest of the southern and eastern CWA, and low to no pops in the far NW. Expect lows in the upper 40s across the northern tier to the mid 50s SE. Skies should remain cloud for much of the night, with partial clearing in the NW late as drier air filters in with downslope low level flow. -GIH Earlier discussion from 705 pm: Quick update to nudge low precip chances a bit farther northward, in accordance with convection- allowing model trends and depictions of low level moisture convergence along and ahead of the incoming 850 mb trough. Still expect likely showers and storms across the extreme southern CWA, although will need to monitor trends, given that the low level theta- e ridge is weakening, with decreasing 850 mb winds, which may yield lower coverage or a suppression of better coverage to the south. -GIH && .SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/... As of 115 PM Tuesday... Expect a clearing trend in the morning as a drier airmass advects into the region from the north, with clear skies during the afternoon and evening. Cold advection is expected to persist for the majority of the diurnal heating cycle on Wed as Canadian high pressure builds into the Mid-Atlantic from the NW. Expect highs much cooler than today, in the mid/upper 50s N/NE to lower 60s S/SW. Lows Wed night may be tempered by increasing mid/upper level cloud cover after midnight. Will indicate lows ranging from the upper 20s (rural and low-lying areas east of I-95) to lower/mid 30s. -Vincent && .LONG TERM /THURSDAY THROUGH TUESDAY/... As of 243 PM Tuesday... With the cP airmass centered over the area Thursday and Thursday night, temperatures through the period will average a good 10 to 15 degrees below normal. A potentially opaque canopy of high clouds Thursday morning should diminish in the wake of the exiting NW flow disturbance, allowing for afternoon sunshine. Highs 50 to 55. High level moisture/cirrus blow-off advecting downstream from the closed cyclone over the Central US could produce fair to partly cloudy skies Thursday night, which could impede radiational cooling a bit. Lows in the lower to mid 30s. The modified Canadian parent high will shift east and offshore on Friday, with southerly return flow allowing for a quick moderation into the 60s on Friday and then into the 70s by Saturday. Meanwhile, ridging aloft will keep it dry through the day on Saturday. Strengthening warm moist air advection on the eastern periphery of the closed mid/upper level cyclone moving east-northeast into the Ohio Valley and Lower Great Lakes will result in increasing pops in the form of showers and possibly a few thunderstorms Saturday night and into the day on Sunday. The most recent 12z/21 GFS has trended farther north than previous runs, and is significantly less wet than previous runs. As such, will keep pops at chance, and highest in the west. If this more northern track solution is realized, Saturday night and Sunday could end up being mostly dry across central NC, with mostly in the way of clouds across the area. Additionally, with the low farther removed from the area, resultant weak forcing will not bode well for any severe weather. Highs Sunday in the 70s. On the heels of the dampening wave moving off the Mid-Atlantic coast Sunday night, another shortwave trough, of lower amplitude, will skirt quickly east across the Central US on Monday and will approach the area late Monday night and into the day on Tuesday. Between these two systems, expect to see a lull in precip chances on Monday, with rain chances ramping back up again Monday night and Tuesday. Continued mild with highs in the 70s. Lows in the 50s. && .AVIATION /01Z Wednesday through Sunday/... As of 915 PM Tuesday... A lead frontal zone now stretching from near EWN to JNX to JQF, and associated focus for scattered showers and storms and sub-VFR conditions mainly at FAY through 09, will settle Swd tonight. Generally Nly winds, between 6-12 kts, will develop behind the front overnight. A secondary cold front and leading edge of strong continental polar high pressure will surge Swd through central NC early Wed; and this will result in strong and gusty NEly winds in strong surface pressure rises and cold air advection between 12-18Z Wed, with lessening winds during the afternoon. Outlook: There will be a chance of MVFR-IFR visibility restrictions in radiation fog in SErn NC Fri morning, including at FAY and perhaps RWI, then again forecast area-wide on Sat morning. && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Hartfield NEAR TERM...Hartfield SHORT TERM...Vincent LONG TERM...CBL AVIATION...MWS
Area Forecast Discussion
National Weather Service Springfield MO
717 PM CDT Tue Mar 21 2017 .SHORT TERM...(This evening through Wednesday) Issued at 257 PM CDT Tue Mar 21 2017 Showers and a few thunderstorms developed across much of the region this morning and into the afternoon hours. A few elevated storms were able to reach severe limits. Much of what`s left early this afternoon is showers and storms within area of strongest isentropic upglide and ascent within an upper level impulse sliding southeastward. Through the afternoon and into the evening, short term models are hinting at some additional development. RAP shows around 500-1000 J/KG of instability across much of the region, although it should be noted the RAP`s CAPE values have been under-performing (to say the least). Elevated instability, a boundary (as seen on visible) dropping southward, and subtle isentropic support will help kick off additional activity along or just south of the HWY 54 corridor. This activity should begin to shift southward through the late afternoon and evening. Although no widespread severe weather is anticipated, a few marginally severe hail reports can`t be ruled. The best shower and storm potential will end up settling further south along the MO/Ark border through the overnight and into Wednesday morning. With the surface front remaining just to our south through Wednesday, we will keep at least some mention of rainfall with overrunning, but at the moment there is no signal for anything more than scattered coverage. .LONG TERM...(Wednesday Night through Tuesday) Issued at 257 PM CDT Tue Mar 21 2017 The front to our south, which should keep our region in the cool sector through much of the short term should slowly move northward as heights aloft begin to increase. Still, proximity of the frontal boundary along with subtle H5 impulses should help keep the rain chances nonzero through Thursday. A potent upper level system will begin to slide eastward toward the Missouri Ozarks and southeast Kansas by Friday. A deep surface low will develop in the high plains region and slide generally along and slightly north of the I44 corridor through late Saturday. Showers and Thunderstorms will develop along or just ahead of the cold front. Although instability looks very marginal at this time, wind dynamics and bulk shear will be supportive of at least an isolated wind threat late Friday. Post frontal showers/storms are then expected as the upper level low slowly moves through the region by early Sunday. Some of these storms may have a hail risk. Just as the weekend storm moves out, another mid level wave will begin to slide across the plains late Sunday and into Monday. Being in the warm sector, we`ll need to keep our eyes open for more strong storms during this time. Similar to the earlier system, instability looks marginal with slightly limited moisture. The end of the period, we`ll finally get a small break as upper level ridging takes place on Tuesday/Wednesday before our next potent mid-level trough takes shape across the Rockies. The good news is our current pattern will bring several opportunities for much needed rainfall across the area. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 651 PM CDT Tue Mar 21 2017 After a front moved through the area earlier today, surface winds were out of the northeast and gusty. VFR ceilings around 5kft will continue into this evening as a mid level boundary moves south through the region. This will bring the potential for some additional showers or an isolated storm to the Ozarks during the evening and overnight hours. Ceilings are expected to remain VFr through the forecast period as the front from earlier today wanders north and south across northern Arkansas. && .SGF WATCHES/WARNINGS/ADVISORIES... MO...NONE. KS...NONE. && $$ SHORT TERM...Frye LONG TERM...Frye AVIATION...Hatch
Area Forecast Discussion
National Weather Service Shreveport LA
1042 PM CDT Tue Mar 21 2017 .DISCUSSION... Have made a few changes to the ongoing forecast by adding areas of fog to parts of East and Northeast Texas and lower parts of Northwest and North Central Louisiana. Adjusted the expected sky conditions and current trends in the dew points and winds. Surface low pressure centered over East and Southeast Oklahoma and West and Southwest Arkansas with a cold front from the surface low near Fort Smith Southeast to near Pine Bluff Arkansas and on into North Mississippi. This boundary will continue to backdoor into the Four State Region during the late night and early morning hours Wednesday with the surface low retrograding into North Texas. Will continue the current chances for showers and thunderstorms with the boundary and in its wake over mainly the more Northern half of the forecast area. By late in the day Wednesday the front will move into Deep East Texas and across Central Louisiana where it looks to become nearly stationary overnight Wednesday, and then work back Northeast on Thursday as a warm front. /06/ && .PREV DISCUSSION... /issued 550 PM CDT Tue Mar 21 2017/ AVIATION... Prevailing SKC attm across our terminal airspace but that will be changing as we go through the overnight hours and through much of Wednesday. A tight pressure gradient across the Southern Plains will begin to relax this evening as a weak cold front currently across Northern Ms, Northern Ar and Eastern Ok will begin backdooring itself into our terminal airspace overnight. This frontal boundary should be pushing through the TXK/ELD terminals around 06-08z, near the SHV/MLU terminals in the 09/11z timeframe before the boundary stalls. There are some questions as to whether or not the boundary will continue moving south and west into the TYR/GGG terminals as per the HRRR so will make this adjustment if and when the 00z progs come in line with this scenario for the 06z package. Ahead of the backdoor cold front, should see MVFR/IFR ceilings come north from SE TX overnight, encompassing the TYR/GGG and LFK terminals with the possibility of LIFR ceilings and VSBYS at the LFK terminal towards daybreak. Low clouds should filter in the region in the wake of the backdooring cold front as well with IFR/MVFR ceilings possible. MVFR ceilings may be stubborn to mix out during the afternoon on Wed, especially in the wake of the backdoor boundary and assuming the boundary stalls before pushing into the TYR/GGG/LFK terminal airspace, low ceilings should mix out quickly Wed morning/afternoon. Post frontal winds with be 5 to 10kts from the NE to ENE on Wed. 13 && .PRELIMINARY POINT TEMPS/POPS... SHV 60 77 59 84 / 10 10 10 10 MLU 58 75 57 84 / 10 10 10 10 DEQ 57 70 51 78 / 20 20 10 10 TXK 56 71 53 80 / 20 20 10 10 ELD 56 72 52 84 / 10 20 10 10 TYR 61 79 61 85 / 10 10 10 10 GGG 61 77 60 84 / 10 10 10 10 LFK 61 83 61 86 / 10 10 0 10 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...None. LA...None. OK...None. TX...None. && $$ 06/13