Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/01/18

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
245 PM AKDT Sat Mar 31 2018 .DISCUSSION... A ridge will build over the Bering sea and stretch northward across the bering strait through Monday. A shortwave will move east across the western north slope tonight and continue to track to the east and will be over the eastern North Slope on Sunday. Another shortwave will track across the Interior Saturday evening bringing a shot of snow for the Middle Tanana Valley. On Tuesday a cold 518 dam low will push southward into the western Interior and deepen to 510 dam by Wednesday afternoon over the Yukon Delta then move over Bristol Bay on Thursday. Surface...A frontal boundary will sweep across the north slope bringing snow and gusty winds this afternoon and will push over the Beaufort Sea coast and into the Interior this evening. A 1042 mb high will build over the Bering sea and build northward over the weekend and into next week. West Coast and Western Interior: Fog and low clouds will persist along the west coast into early Sunday (the HRRR actually has a solid area of low visibility fog stretching from the Bering Strait Coast southward to the Yukon Delta through early Sunday morning). Dense fog headlines added for zones 213 and 211 for dense fog around Nome and the Bering Strait. High pressure will build north across west coast on Sunday, keeping the west coast free of precipitation Sunday through Tuesday. Low level winds will strengthen and become northeasterly on Tuesday. North Slope and Brooks Range: Winter weather advisories still in effect for zones 202 and 203. A blizzard warning is in effect for zone 204. Snowfall amounts around the 2 to 4 inch range with locally higher amounts over the Eastern Brooks range through Sunday morning. A tight pressure gradient will produce westerly winds gusting to 50 mph near Barter Island area Sunday into Monday. High pressure will build along the north side of the Brooks Range this evening. This will cause strong northerly gap winds to develop in Brooks Range Passes. The gap winds in the Brooks Range combined with falling snow will result in blowing snow reducing the visibility to one half mile or less at times into Sunday. Central and Eastern Interior: Snow will begin to develop across the Middle Tanana Valley late this afternoon due to a frontal boundary and an increase in moisture. Expecting 1 to 3 inches with the heaviest amounts south of Fairbanks and near the Alaska range due to upslope enhancement. The snow will gradually taper off Sunday morning. In addition to the snow, wind gusts as high as 25 mph will cause blowing snow reducing the visibility at times mainly over higher terrain. Blowing and drifting snow possible over the summits of the Steese, Dalton and Elliott Highways. Winter weather advisories are in effect for snow and blowing snow for zones 220 218 and 219. High pressure will build over the Interior on Monday drying things out. Little to no precipitation through mid week for the Interior. Coastal Hazard Potential Days 3 and 4...None. && .AFG WATCHES/WARNINGS/ADVISORIES... Blizzard Warning for AKZ204. Winter Weather Advisory for AKZ202-AKZ203-AKZ206-AKZ218-AKZ219- AKZ220. Gale Warning for PKZ240-PKZ245. Brisk Wind Advisory for PKZ230-PKZ235-PKZ240-PKZ245. && $$ JK MAR 18
Area Forecast Discussion
National Weather Service Albany NY
1033 PM EDT Sat Mar 31 2018 .SYNOPSIS... A strong cold front will cross the region overnight into Sunday morning. A few rain and snow showers will accompany its passage. A brisk day setting up for Sunday as a return to at least partial sunshine. Another fast moving system may bring accumulating snowfall south of I 90 overnight Sunday into Monday morning. && .NEAR TERM /THROUGH SUNDAY/... As of 1030 PM EDT, winds have increased to 15-20 mph with gusts up to 35 mph. These winds will be sustained through the early morning as temperatures stay fairly mild. That being said, no major changes made as the forecast remains on track. Prev Disc...As of 740 PM EDT, Cloud cover continues to increase from west to east across the area this evening with temperatures generally in the 40s to low 50s. Precipitation, currently over western New York and northern Pennsylvania is still working its way east, with mainly light rain being reported. That being said, only made minor tweaks to the forecast at this time, to align hourly temps with recent obs. Sent updates to NDFD and web servers. Prev Disc...As of 330 PM... A beautiful start to our weekend with wall- to- wall sunshine, however, as seen in the enhanced GOES 16 data the clouds will be on the increase from the west in advance our next weather system. Rather strong cold front will cross the region overnight as main surface low deepens and tracks across the central Great Lakes and toward James Bay. Upstream regional radar reveals an extensive area of showers across the Great Lake State of Michigan with a break in the coverage into Indiana and Ohio. Per the latest HRRR along the analysis of the layer H2O vapor loop, the main center of the low will become further removed from the front as mid level moisture fields become increasingly drier overnight. This points toward a decrease in PoPs/Wx overnight to scattered showers. However, overall enhanced low level convergence and low level jet with upper jet support would allow for showers to redevelop over the region overnight. Hence our graduated PoP forecast with the higher terrain the higher values than those in the Hudson Valley. There could be another enhancement to the showers southeast of Albany as the upper jet tracks northward with enhanced low level ageostrophic lift for additional showers. As for thermal profiles, cold advection quickly increases with FROPA where some rain mixes with and changes to snow overnight (again, mainly the higher terrain and west of the Hudson). Accumulations should be an inch or less due to the fast movement of these features. Then some minor Lake Ontario response may occur Sunday morning yet inversion levels are expected to drop as subsidence and surface ridge builds in from the west. The main hazard potential will be the increasing wind magnitudes through the morning hours. Per BUFKIT hourly profiles at select points across the region and hires wind gust potential, seems we will see wind gusts just below the thresholds for wind advisory criteria. Values will generally be in the the 30kt range which in agreement with observations upstream per METARS. As H850 temperatures fall back below -10C, high temperatures will likely be earlier in the day and with early April sun angle holding temperatures nearly steady through the early afternoon. && .SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/... Potential for an accumulating snowfall event south of Albany on the increase overnight Sunday into Monday morning. H2O vapor loop reveals a rather strong wave across the Pacific northwest that will continue to track southeast across Idaho. Models are now suggesting this wave will be a little further north as downstream trough axis orientation will be more zonal than amplified. The ECMWF was the first to suggest this potential and the NCEP Model Suite appears to be trending northward per the Dprog/Dt analysis. So clouds will increase across the southern 2/3rds of the region Sunday night with light snow developing from west to east overnight mainly south of I90. Cross sections from the NAM/GFS point toward a tight 850-700 2D FGEN fields near the I84 corridor. So a band of moderate snowfall is possible and per the trends, did increase snowfall amount forecast a bit from the previous forecast. At this time time, 1-3" of snow with up to 4" possible along southern Dutchess and Litchfield Counties. The snow should end rather quickly around 15Z Monday as dry air advection occurs with surface high building in across the region. This surface high strengthens just to our east Monday night as next storm system approaches from the west. This will increase the cloud coverage from west to east yet again with the chance for a light snow to develop late across most of eastern NY. Temperatures through the short term will generally be at or below normal. && .LONG TERM /TUESDAY THROUGH SATURDAY/... A Low pressure system over the mid western portion of the United States will track north and eastward. As this system approaches the will bring widespread precipitation to the region late Tuesday through Wednesday night. At this may start out as a mix of rain and snow as temperatures will be below freezing initially. By Wednesday...warmer air will will move back into the region keeping the precipitation in the form of rain. Wednesday night...the low pressure system will continue to move north and eastward. However...with wrap around flow from the departing system...there may be the threat of rain showers changing back over to snow showers. Any precip that does fall Wednesday night will be light. Thursday and Friday will be unsettled as another system drops down from Canada. This will bring the threat of more precipitation and cooler temperatures. With a cold air mass in place...will probably see rain and snow mixed. On Wednesday ahead of the storm systems cold front...temperatures are expected to warm to seasonable levels with highs forecast in the upper 40s to 50s. However with the passage of the cold front a colder airmass returns with well below normal temperatures expected Thursday. The end of the week could be blustery with a series of systems dropping down from the north creating a tight pressure gradient with strong winds and below normal temperatures. && .AVIATION /03Z SUNDAY THROUGH THURSDAY/... Clouds will continue to increase overnight as a low pressure system with associated fronts approach from the Great Lake region. The low pressure system will pass north of our region with a warm frontal passage this evening, then a cold front by Sunday morning. There is chance of light showers overnight with the frontal passage. However, any precipitation that does fall will be very light. Clouds should break up and lift across all TAF sites by Sunday afternoon. S-SW winds will gradually shift to the west by 12z/Sunday as a cold front moves through the region. With a decent pressure gradient in place, 10-20 kt sustained winds with gusts up to 35 kts are expected. Prior to the cold frontal passage Sunday morning, some LLWS is possible at KPSF. Outlook... Saturday Night: Moderate Operational Impact. Breezy. Scattered SHRA...SHSN. Sunday Night: No Operational Impact. NO SIG WX. Monday: No Operational Impact. NO SIG WX. Monday Night: Low Operational Impact. Slight Chance of SHRA...SHSN. Tuesday: High Operational Impact. Likely RA...SN. Tuesday Night: High Operational Impact. Likely RA. Wednesday: High Operational Impact. Likely SHRA...RA. && .FIRE WEATHER... Wind gusts over 25 mph are expected Sunday... Scattered rain and snow showers are expected overnight into Sunday morning as a strong cold front crosses the region. It will turn breezy tonight and remain breezy on Easter Sunday with cooler temperatures but mostly dry aside from lingering light morning snow showers. Another round of light snow is possible south of I-90 Sunday night into Monday morning. && .HYDROLOGY... Mild temps today may result in a little bit of snowmelt. Scattered light showers are likely along an approaching cold front tonight. QPF amounts less than 0.25 inches expected. Light snow may fall above 1500 feet, especially over the southern Adirondacks with around an inch possible. A colder airmass will take hold Sunday into Monday, with limited snowmelt during the day and subfreezing temps at night. A more widespread precipitation event is likely for Tuesday into Wednesday. QPF amounts could exceed an inch. This event is likely to be mainly rain with fairly mild temperatures, but may begin as snow early Tuesday, and may mix with snow toward the end of the event over the higher terrain. For details on specific area rivers and lakes, including observed and forecast river stages and lake elevations, please visit the Advanced Hydrologic Prediction Service /AHPS/ graphs on our website. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. MA...None. VT...None. && $$ SYNOPSIS...BGM NEAR TERM...BGM/JVM SHORT TERM...BGM/Thompson LONG TERM...VTK AVIATION...VTK/JVM FIRE WEATHER...BGM/Thompson HYDROLOGY...BGM/Thompson
Area Forecast Discussion
National Weather Service Denver/Boulder CO
820 PM MDT Sat Mar 31 2018 .UPDATE... Issued at 802 PM MDT Sat Mar 31 2018 Areas of pcpn have developed over the plains from Fort Morgan to Sterling and near the WY border. This area is north of a frontal boundary and aligned with right exit region of an upper level jet. Have adjusted pops a bit further south to account for current trends. Late tonight the upper level jet may sag further south as an upper level disturbance moves across. This may allow for a chc of snow to spread further south between 09z and 12z with the northern part of the Denver metro area being affected and along the I-70 corridor in the mtns. && .SHORT TERM...(This evening through Sunday) Issued at 235 PM MDT Sat Mar 31 2018 Flow aloft is west-northwest as a shortwave trough over the Pacific Northwest will be dropping southeast, crossing over the Northern Rockies early Sunday morning. Moisture this afternoon has been less than previously though, with little to no snow being observed in the northern mountains. Most precipitation activity is further north in Wyoming. Wind and temperature forecasts has been difficult over the plains this afternoon as a cold front hangs over the northeastern plains while a Denver Cyclone is spinning up over Douglas County. Thinking is the cold front will push in early this evening, but perhaps not as strong as originally thought, with the Cyclone staying nearby which may keep low clouds out of the western urban corridor, or at least not as thick overnight. Latest forecast soundings have backed off slightly on the amount/thickness of low clouds, but it still remains. Therefore, for Easter Sunday morning, may have some low clouds around sunrise and potentially for a few hours after, but should break up by noon with sun shining in. The one exception will be the far northeastern corner where the inversion will be thicker and stronger. Temperatures Sunday will be similar to today`s. For the shortwave passage overnight, trends in hi- res models have been to shift this moisture further north, with the HRRR not even wanting to bring precip into the plains, but with limited amounts into the northern mountains. Will still have a chance to likely chances over the far northern plains, but shift this area slightly more to the north. Through Sunday morning, still expecting 1 to almost 3 inches along the northern state border, with 1 to 4 inches over the northern mountains north of I70 - some higher areas could see up to 5 but this will be limited. .LONG TERM...(Sunday night through Saturday) Issued at 235 PM MDT Sat Mar 31 2018 The upcoming week will be characterized by a moderate to strong northwest flow pattern along with several embedded disturbances to move across Colorado. Before the first wave, there will be strong westerly flow over the mountains Sunday night and Monday with strong and gusty winds over the mountain passes. Some of these winds will also surface over the plains by Monday afternoon with breezy yet warm conditions in downslope flow. This does not appear to be a significant high wind threat. The first of the week`s waves and will move across Colorado on Monday night and early Tuesday with shot of snow for the mountains and lesser chances over the northeast plains. This will be a fast moving system and any upslope will be short lived on the plains as stronger northwest flow develops behind it. Best chances of showers will be east of the Front Range. Drier and cooler on Tuesday behind the wave and then warmer again on Wednesday with dry northwest flow. The next wave later in the week is poised to move over Colorado Thursday night and Friday with the next chance for mountain snows and showers over the plains and cooler over all areas on Friday. Somewhat more unsettled over the weekend as stronger troughiness develops over the Great Basin and spreads more moisture across Colorado. c&& .AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon) Issued at 235 PM MDT Sat Mar 31 2018 Southeasterly winds currently over the airport, however a Denver Cyclone setting up south of Denver should push east to bring northwesterly winds over the terminals. There is a chance for the southeasterly winds to remain to remain at DEN. VFR conditions are expected through the rest of the day. A second surge of northeast winds will occur this evening, by 02z with the potential for ILS restrictions with cigs bkn around 5 kft agl around 06z, then lowering to near 1 kft as the upslope deepens by 10z. Stratus should then break up by 15-17z with VFR conditions and easterly winds Sunday. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 802 PM MDT Sat Mar 31 2018 Sfc low was over the Palmer Divide as nely winds continue at DIA. Meanwhile stratus has advected into the area as well with ceilings down to 2000 ft. Latest data suggest these lower ceilings may last overnight thru sunrise. As for winds they will stay mostly east or northeast overnight. Finally there is some risk of a brief period of light snow late tonight between 10z and 13z which may stay just to the north of DIA. && .FIRE WEATHER... Issued at 235 PM MDT Sat Mar 31 2018 There is a potential for critical fire weather conditions Monday afternoon and early evening as gusty southwest winds and low humidities develop. Highest focus area will be over fire weather zones (246..247) and includes eastern Elbert and Lincoln counties. These areas have also only had limited rain/snowfall during the past week. && .BOU WATCHES/WARNINGS/ADVISORIES... Fire Weather Watch from Monday afternoon through Monday evening for COZ246-247. && $$ UPDATE...RPK SHORT TERM...Kriederman LONG TERM...Entrekin AVIATION...RPK FIRE WEATHER...Entrekin
Area Forecast Discussion
National Weather Service Billings MT
903 PM MDT Sat Mar 31 2018 .UPDATE... Courtesy of a moist dendritic layer and weak ascent, areas of light snow and flurries continue across our western cwa including the Billings and Sheridan areas as of 830pm. Forcing is slowly shifting south, with drying from the NW, so the light precipitation should end soon, probably by around midnight. Only other issue tonight is fog. Boundary layer is fairly dry in our east where skies are clearing, and cloud cover will remain up in our west, so not sure if we will realize our fog potential tonight. With partial clearing we could see fog in valleys in our central parts, areas that saw precip over the past day, and this includes places like Roundup, Billings and Sheridan. Recent HRRR runs are not suggestive of fog at all. Will make some adjustments to the fog coverage later tonight into early Sunday. Something to keep an eye on through the night. Otherwise, it will be COLD tonight with a record low quite possible at Miles City (record is 4 above on April 1st). Be ready for a chilly Easter morning everyone. JKL && .SHORT TERM...valid for Sun and Mon... Snow showers were quickly winding down this afternoon as a combination of drier air from the west, decreased upper level support, and diminishing upslope flow moves in. It`s going to be a very cold night across the forecast area with low temperatures in the low teens and upper single digits. Can`t rule out some low lying locations in eastern Montana seeing temperatures near or just below zero (see Miles City forecast low of -1). Most roads are clear of snow at this hour, thanks to our high sun angle this time of year, but slick conditions are still possible into tonight, especially as the sun begins to set and the roads quickly cool. Last forecast concern for tonight will be the potential for fog in eastern Montana as mostly clear skies and light winds could allow patchy fog to develop overnight. Quiet conditions anticipated Sunday along with warmer temperatures in the upper 30s and low 40s. Eyes will be on the next winter system to approach the region Sunday night. Precipitation will begin to overspread the region Sunday night and Monday morning. Any rain showers will turn to snow Monday morning as a upper level low works into the region. This system, dynamically, is different from Saturday`s system and is more typical of a spring winter storm system. Expect a wet heavy snow to fill in across the region Monday into Monday night with 4 to 6 inches of snow possible over the lower elevations. The mountains will see more, with 6 to 15 inches of snow possible through Tuesday morning. Timing of this system, with the heaviest precipitation falling during the day Monday, does leave some uncertainty in regards to snow amounts. Accumulations this time of year can be hard to come by during the day as a higher sun angle can limit accumulations depending on the cloud cover, so its something to keep an eye on. With these possibilities in mind have put out a winter storm watch for Sunday night through Monday night across the entire forecast area. Dobbs .LONG TERM...valid for Tue...Wed...Thu...Fri...Sat... Only trended the extended towards current model trends. Models did not come in with any major changes. Monday`s trough will move out Tuesday, so there should only be maybe some linger precip early in the day. Flow through the period remains northwesterly, so cannot rule out at least some slight chance PoPs through much of the extended. The 12Z runs did some in a little wetter towards the end of next week. The GFS is a little faster than the EC with the precip. Temperatures still looks to be on the cool side. Reimer && .AVIATION... Lingering areas of light snow and flurries should dissipate by around 06z. Areas of MVFR ceilings along and west of a BIL-SHR line should gradually improve to just VFR. Mountains will be occasionally obscured tonight. There is a slight risk of patchy valley fog later tonight into early Sunday, but confidence in fog impacting a terminal is quite low. Will continue to monitor through the night. On Sunday, the next approaching disturbance will bring increased chances of rain/snow showers west of BIL by afternoon. Expect local MVFR and increasingly obscured mountains. JKL && .PRELIMINARY POINT TEMP/POPS... Sun Mon Tue Wed Thu Fri Sat ----------------------------------------------------------- BIL 011/042 027/035 013/037 022/043 028/044 026/041 026/046 11/B 77/W 52/S 12/R 24/O 54/O 43/O LVM 011/047 031/038 015/040 025/048 031/050 029/047 031/051 13/W 87/W 52/O 23/O 36/R 75/R 44/R HDN 008/042 027/035 012/037 019/043 026/043 023/041 022/045 10/B 68/J 62/S 11/B 24/O 55/S 43/O MLS 901/037 024/030 010/031 016/038 022/037 018/033 019/039 00/B 67/J 72/S 11/B 34/O 33/S 33/S 4BQ 008/042 025/038 013/034 018/041 025/042 021/037 021/043 00/B 47/W 72/S 11/B 24/O 55/S 53/S BHK 002/036 022/029 008/028 012/036 019/034 013/030 015/034 00/U 57/J 81/B 11/B 13/S 22/S 12/S SHR 009/044 028/042 014/036 018/045 026/048 027/043 027/049 21/B 48/W 72/S 12/S 23/O 65/O 43/R && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...Winter Storm Watch in effect from Sunday evening through Monday evening FOR ZONES 28-29-34-35-39>42-56-63>68. Winter Storm Watch in effect from late Sunday night through late Monday night FOR ZONES 30>33-36>38-57-58. WY...Winter Storm Watch in effect from late Sunday night through late Monday night FOR ZONES 98-99. && $$
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1154 PM EDT Sat Mar 31 2018 .AVIATION... Fairly dense canopy of top of the mixed layer stratocumulus this evening in the wake of the cold front that passed through all of Southeast Michigan this evening. Initial cold advection in the presence of high ambient moisture environment has led to saturation below the established subsidence inversion. Really at odds tonight with how quick clouds will scatter/move out as efficient, deep column downglide is forecasted. Preference is to side with BKN-OVC cloud early in the TAF forecast, giving way to SCT conditions by late morning Sunday. However, note there is some uncertainty as clouds could become emboldened again with diurnal heating. Look at the NAM3 output vs. RAP. For DTW...Wind shift/fropa expected to occur right around 00z. /DTW THRESHOLD PROBABILITIES... * Medium to low for ceilings aob 5000 ft tonight through tonight. && .PREV DISCUSSION... Issued at 347 PM EDT Sat Mar 31 2018 DISCUSSION... The Wind Advisory will remain in effect as strong wind impacts remain a concern during late afternoon and evening. After that, conditions quickly improve overnight leading to a cold but otherwise pleasant Easter Sunday. Early afternoon wind gusts touched 45 mph in a few spots over central Lower Michigan with the onset of rain, which also had a stabilizing effect through mid afternoon. Incoming RAP model soundings indicated a much shallower mixed layer as a result, however observations do indicate some recovery taking place upstream with several mid afternoon gusts in the upper 30 to lower 40 knot range along the Illinois/Indiana border. This recovery is also picked up by the rapid update model soundings depicting a deeper mixed layer to neutral profile making northward progress into Lower Michigan prior to the frontal passage. This leaves the door open for gusts reaching 45 mph+ ahead of the front within and in between shower activity. Surface temps and dewpoint reaching as high as the mid 50s/mid 40s immediately ahead of the cold front also suggests we monitor for an uptick in low-topped convection along the boundary during late afternoon and early evening. This would also will be capable of overachieving wind gusts, as will the frontal passage itself. Isolated peak gusts reaching 50 mph+ remain possible until the front exits SE Michigan 8-9 PM. Northwest wind will continue Sunday morning but at much lower speed and while backing toward the west as high pressure builds into the southern Great Lakes. Model profiles still depict enough residual boundary layer moisture and low level instability for pockets of clouds and a few flurries as waning low level cold advection combines with April 1st daytime heating. Forecast soundings do show only shallow ice supersaturation along with cloud base on the high side, near 5000 ft, and so coverage of flurries will be less than indicated by radar. The incoming surface high will otherwise ensure dry weather with partly sunny skies while cold air holds highs in the 30s. There will also be precipitation nearby to the south as a low pressure system moves through the Tennessee Valley, which is shown in model data to spread a light mix of rain and snow as far north as Toledo by Sunday evening. This will be monitored as increasingly dry air in the low levels associated with the center of high pressure moving over Lower Michigan is expected to prevent any precipitation from moving north of the Ohio border. Monday will start out the new week with high pressure centered over the Ohio border region and remaining in control of conditions across SE Michigan. A generous amount of early April sunshine will help temperatures moderate into the lower and mid 40s before clouds thicken late in the day. These clouds will be arriving ahead of the next low pressure system, currently analyzed over the Canadian Pacific coast, as it moves into the Plains and Midwest by Monday night. This system is projected to spread precipitation northward into the Great Lakes later Monday night into Tuesday. There remains considerable spread in model opinion on the quality of moisture supplied to the system which affects the depth of saturation and associated guidance projections on precipitation type. Considering that the low will interact with the frontal zone left behind over the Tennessee Valley, the low should have access to adequate moisture favoring deeper saturation profiles that would result in snow at onset over Lower Michigan followed by a quick transition to rain during Tuesday morning. A mixed precip window is possible early Tuesday but will maintain a basic change from snow to rain for now considering the brief nature of the transition. The precipitation Monday night and Tuesday will occur in advance of the low pressure system and then continue Tuesday night into Wednesday as the low moves through the southern Great Lakes. At this point, variability remains high in model solutions regarding the surface low track and QPF amount/distribution. The NAM provides a warmer solution for SE Michigan with a surface low position over central Lake Huron by Tuesday evening. The ECMWF has the surface low over NW Indiana by then, and is colder with much higher with QPF. The going forecast favors a snow to rain to snow transition through this time period for now with later updates providing some clarity on timing and track of the system. This system will also mark the transition to broad long wave trough in the upper levels over central Canada and the Great Lakes that will last into next weekend and keep temperatures well below normal through the period. MARINE... Low pressure is tracking through the Straights late this afternoon and will continue to deepen as it tracks off to the northeast into Eastern Canada. The associated cold front will sweep through the Central Great Lakes early this evening, leading to a wind shift to the northwest. All marine headlines have been continued. Although, the low is slightly weaker than expected and could just see brief storm force winds over northern Lake Huron vs 3 hours or greater. Otherwise, extended period of gale force winds look good for the other marine waters. Post frontal northwest winds tonight will slowly diminish and become westerly tomorrow, with light winds to start the work week on Monday as high pressure slides through. Another strong low pressure system will move move into the area on Tuesday, with northeast winds of 25 to 30 knots expected over Lake Huron. Gale force winds are not out of the question of central Lake Huron, funneling into Saginaw Bay. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. Lake Huron...Gale Warning until 4 AM EDT Sunday for LHZ363-421-422-441>443- 462>464. Storm Warning until 4 AM EDT Sunday for LHZ361-362. Lake St Clair...Gale Warning until 4 AM EDT Sunday for LCZ460. Michigan waters of Lake Erie...Gale Warning until 4 AM EDT Sunday for LEZ444. && $$ AVIATION.....CB DISCUSSION...BT MARINE.......SF You can obtain your latest National Weather Service forecasts online at
Area Forecast Discussion
National Weather Service Indianapolis IN
1022 PM EDT Sat Mar 31 2018 .UPDATE... The AVIATION Section has been updated below. && .SYNOPSIS... Issued at 239 PM EDT Sat Mar 31 2018 Active weather will continue across Central Indiana the next several days as multiple weather systems will pass through the region. A cold front will sweep across Central Indiana late this afternoon...leading to some rain showers late this afternoon and early this evening. Sunday will start as a dry day as the front lingers across south of Indiana...However...a quick moving upper level weather disturbance will arrive in the area on late Sunday Afternoon. This will bring chances for a rain/snow mix of precipitation across Central Indiana on Sunday evening. Light accumulations will be possible. After dry weather on Monday with high pressure across the area...a couple more weather systems will push through Central Indiana on Monday night through Wednesday...bringing more chances for rain and maybe even a few spring thunderstorms. Other than Tuesday...look for temperatures to be mostly below seasonal normals. && .NEAR TERM /Tonight/... Issued at 239 PM EDT Sat Mar 31 2018 Surface analysis early this afternoon shows a strong area of low pressure in place over NE Wisconsin with a trailing cold front stretching SW across Western Illinois to Central Missouri and SE Kansas. Radar shows a few light showers across Central Indiana Ahead of the front stretching from Muncie to GreenCastle and Terre Haute. Southerly surface flow was in place ahead of the front. Water vapor imagery shows the quick W-NW flow in place aloft across the region...showing a few weather systems upstream poised to push across the Ohio Valley. HRRR suggests the progression of the precipitation across the area will shift slowly to the southern parts of the forecast area by 00Z...exiting southern parts of Central Indiana by midnight. Models suggest that the elongated front will sag across southern parts of the state this evening as the front become more E-W oriented. This suggests that some of the ongoing precip currently over Missouri and SRN Illinois should advect to the southern parts of the forecast area this evening. Forecast soundings and time heights suggest good moisture in place across the area with some dynamics aloft still passing. Thus will focus best pops across the far southern parts of the forecast area mainly during the evening hours...much much lesser pops through the early evening as one progresses north across the forecast area. Given the expected cold air advection...will trend lows at or below the forecast builder blends. && .SHORT TERM /Sunday through Tuesday/... Issued at 239 PM EDT Sat Mar 31 2018 Another weather system looks to impact Central Indiana on Sunday afternoon and evening. As the frontal boundary left over from today`s system stalls across Kentucky...the GFS and NAM suggest another short wave within the flow aloft to push across Ohio valley. Forecast soundings respond to this feature with a saturated column by late in the day on Sunday with Pwats near 0.65 inches. The GFS 295K Isentropic surface shows excellent isentropic lift across the southern parts of Central Indiana with specific humidities over 4 g/kg. forecast soundings also show much of the column below freezing...all expect the far lowest levels near the surface. Thus precip type...should mainly be snow in the IND metro area...but perhaps a mix across far southern Indiana where the above freezing layer will be a bit thicker. Will include a mix at those locations. Nonetheless...given the forcing and ample moisture...will trend to a light accumulating snow. Evaporational cooling from ongoing precip will also help to cool lower levels. THus will trend pops at or above the forecast builder blend on Sunday afternoon and Sunday Evening....along with Highs at or below the forecast builder blends. Forcing and dynamics quickly exit the area overnight on Sunday Night as isentropic lift is lost and subsidence resumes across the area. Thus will trend pops toward a dry forecast overnight and stick close to the forecast builder blends. A pause between weather systems looks in storm for Monday Morning and early monday afternoon as HIgh pressure quickly moves across the area. Here forecast soundings show a dry column with subsidence. Thus will trend toward partly cloudy for much of the day. however by late afternoon the forecast soundings start trending toward saturation as a warm front approaches from the south...and yet another low pressure system begins to spin up over the central plains. Aloft...but the models do show limited forcing on Monday afternoon...appearing weak. Better lower level organization arrives on Monday night as the warm front lifts north across Central Indiana. Thus will focus best pops across the area then. The warm front to the north places Indiana clearly in the warm sector briefly on Tuesday. Model suggest strong low pressure on Tuesday sweeping from Illinois to toward Lake Huron. THis will drag another strong cold front across Central Indiana...with ample dynamics. Again forecast sounding here show deep saturation with some potential for some elevated convection. Given this favorable set-up will again include high pops on Tuesday...particularly during the afternoon hours during the expected frontal passage. && .LONG TERM /Tuesday Night through Saturday/... Issued at 325 PM EDT Sat Mar 31 2018 Guidance suggests a couple of different systems will impact the area during the long term period - the first, the tail end of the frontal system that will bring rainfall to the area early in the week, and the next, another cold front late in the week. Temperatures, particularly late in the week, will be borderline and may support some periods of light snow showers, although this is low confidence. Temperatures will generally be below normal throughout the long term with a couple of reinforcing shots of cooler air. Blended initialization handled things well and only minor adjustments were required. && .AVIATION /Discussion for the 01/03Z TAF Update/... Issued at 1021 PM EDT Sat Mar 31 2018 Update... Removed gusts from KIND. Previous Discussion... The gusty southwest winds have begun to taper off and will continue to do so over the next few hours. Meanwhile, current radar mosaic shows rain showers mainly concentrated over KBMG, ending there after Sun 06Z as well. Conditions will fluctuate around the MVFR/VFR mark through Sun 03Z, then becoming primarily VFR through the end of the TAF period. Winds will become northerly early tonight at 5 to 10 kts. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS...TDUD NEAR TERM...TDUD SHORT TERM...TDUD LONG TERM...Nield AVIATION...TDUD
Area Forecast Discussion
National Weather Service Jacksonville FL
929 PM EDT Sat Mar 31 2018 ...PATCHY FOG AND LOW CLOUDS DEVELOP TONIGHT... .UPDATE... Coastal Trof is setting up over the Atlc Coastal Waters with a few showers there, while the cool/moist N-NE flow over the land areas will set the stage for low clouds and patchy fog development tonight. High clouds have pushed SE of the region so many areas will be mostly clear/partly cloudy until clouds develop later tonight. Models still unsure of how thick any fog would get towards morning with latest 15z SREF run showing just patchy 3-5 mile fog, while the latest 23z HRRR is hinting towards morning patchy dense fog development around sunrise with local vsbys below 1 mile in some locations. Will depend on position of coastal trof and how much the N-NE winds weaken towards morning, for now they seem to holding in the 5-10 mph range and expected to decrease to around 5 mph towards morning, while any decrease to near calm winds will support some local dense fog. Temps expected to fall near 50 degrees across inland SE GA/Suwannee Valley with rest of the area falling into the 50s. On Sunday, low clouds/patchy fog slow to disperse in the morning hours, but overall expect at least partly to mostly sunny conds by the afternoon with light winds and local sea breezes along the coast. Temps should push to near 80 degrees over inland areas while sea breeze along the coast will hold max temps in the lower/middle 70s. Moisture from old frontal boundary may lift northward enough to trigger a few widely scattered showers along the Atlc sea breeze as it moves inland from JAX southward along the St Johns River Basin, but chances still remain fairly low at 20% or less for now. && .AVIATION... MVFR CIGS have already developed at CRG/SGJ along the NE FL Atlc Coast and these will spread inland and northward with widespread MVFR CIGS by 06z then lowering to IFR CIGS by 09z with some patchy 4-6 mile vsbys possible as well. Some Hi-Res guidance suggesting even lower LIFR CIGS/VSBYS in the 09-15z time frame but for now just gone with IFR conds. These will slowly lift/improve into MVFR CIGS by 14-15z and VFR conds by 18z Sunday. && .MARINE... Coastal Trof setting up over the offshore waters and will continue at least N-NE winds 10-15 knots across the local waters with seas lingering in the 4-6 ft range tonight with SCEC headlines. NE winds will weaken slightly on Sunday with local sea breezes at the coast and seas falling into the 3-5 ft range. Rip Currents: Moderate Risk in the onshore flow. && .PRELIMINARY POINT TEMPS/POPS... AMG 47 82 54 84 / 0 0 0 0 SSI 56 70 57 77 / 0 0 0 0 JAX 53 77 56 82 / 10 0 10 10 SGJ 58 73 57 78 / 10 10 10 10 GNV 53 81 56 83 / 0 10 10 10 OCF 56 82 57 83 / 0 20 20 10 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AM...None. && $$ Hess/Nelson/McGinnis
Area Forecast Discussion
National Weather Service Paducah KY
634 PM CDT Sat Mar 31 2018 .UPDATE... Issued at 634 PM CDT Sat Mar 31 2018 The AVIATION section has been updated for the 00Z TAF issuance. && .SHORT TERM...(Tonight through Monday night) Issued at 320 PM CDT Sat Mar 31 2018 Showers continue to spread east into the area while increasing in coverage. The RAP model continues to show increasing elevated instability seen via steepening mid level lapse rates and computed li`s aoa 800mb below zero into SEMO, far west KY, and perhaps the southern tip of Illinois. Will continue with high PoPs for showers and a couple of thunderstorms as the front moves south across the region tonight. Highest QPF should be across the southern 1/2 of the area. Looks like a lull in the precipitation Easter morning, with the front to our south and little upper support. Clouds will likely hang around. During the afternoon, forcing aloft moves toward the area in conjunction with a s/wv that should be over the Upper Midwest by 00z Monday. Generally liquid precip through the end of the day. We`ll keep a look out across the far NW counties of SEMO/Southern IL late day and into the evening. First time frame of interest is 00z-06z, as we may see a light wintry mix north of a Marble Hill MO, to Mount Carmel IL line. However temperatures will generally be at or just above freezing. So essentially no impact. After 06z, we lose moisture aloft for any ice nucleation. Temperatures close to and north of the aforementioned line fall below freezing. So any lingering low level moisture that might result in light freezing drizzle or very light rain could freeze. It`s very borderline at this time. The NAM is about a degree warmer than the GFS. Not really worth of much more than a mention in the Hazardous Weather Outlook at this point. It is something to keep an eye on though. Return flow sets up Monday. Again a bit of a lull Monday morning, followed by increasing shower chances in the afternoon from west to east. Maybe some thunder too. Shower and thunderstorm chances ramp up Monday night as the warm sector becomes better established across the region. Best chance PoPs Monday night should be across the northern 2/3 of the CWFA. .LONG TERM...(Tuesday through Saturday) Issued at 320 PM CDT Sat Mar 31 2018 The medium range deterministic models were in reasonably good agreement on the active, fast pattern in the extended forecast period. After daybreak Tue, though clouds may be quite plentiful, indications are that the trop could destabilize enough for some robust convection, given the amount of bulk shear available and forecast temps in the upper 60s and lower 70s. By midday or so, scattered clusters or lines of tstms are expected to develop across the entire region. Severe thunderstorms are a possibility, with damaging winds and large hail the primary concerns. It will be breezy ahead of a cold front, with southwest winds 15 to 20 mph, gusting to 25 to 30 mph. Fropa will begin in the northwestern counties around nightfall, and the fast-moving cold front may be through the entire region by midnight. A few showers may linger in the Pennyrile region of KY after midnight. High surface pressure will rule the forecast picture for our region midweek. Under mostly clear skies, temps are progged to crash back to the upper 40s to lower 50s for highs Wed and near or just below freezing Wed night, which may be a concern for growers of early spring vegetation especially in the southern half of the region. Southerly winds on the backside of the high will assist with a modest warm up ahead of a substantial system later in the week. As a low pressure system over Hudson Bay finally rotates into the vicinity of the Great Lakes, substantial height falls are forecast across the eastern CONUS. By early Fri, clouds will be on the increase in our region, along with coverage of showers, though the 12Z ECMWF came initially drier, starting the pcpn 6-12 hours later than the other models. Fropa is forecast Fri afternoon, and it appears most pcpn will be post-frontal. It will probably end with a light wintry mix early Sat. && .AVIATION... Issued at 634 PM CDT Sat Mar 31 2018 One area of showers will push eastward out of KCGI and possibly KPAH early this evening, but will linger at the other sites through the evening. As a cold front approaches later this evening MVFR ceilings are expected to develop along with MVFR showers that are expected to become widespread. Brief IFR conditions cannot be ruled out. The cold front will move through the TAF sites 04Z-07Z and north wind will become gusty at KCGI and to a lesser extent at KPAH. The band of showers will move south out of the TAF sites before daybreak. MVFR ceilings will linger through the day in the south, but VFR conditions are expected fairly after the rain quits in the northeast. Another area of rain will spread north over the region in the afternoon. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...None. MO...None. IN...None. KY...None. && $$ UPDATE...DRS AVIATION...DRS
Area Forecast Discussion
National Weather Service Blacksburg VA
850 PM EDT Sat Mar 31 2018 .SYNOPSIS... A cold front will approach from the northwest tonight before sliding southeast across the area Sunday, and into North Carolina by Monday morning behind a passing wave of low pressure to the north. This front works back north as a warm front Monday night into Tuesday in advance of a strong cold front that looks to cross the region from the west on Wednesday. High pressure follows the front with drier and cooler weather for late week. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... As of 845 PM EDT Saturday... Very dry air remains in place across the region this evening as seen via evening soundings and surface dewpoints that remain in the teens and 20s. Satellite showing upstream clouds ahead of the cold front to the west gradually approaching but fading upon encountering the residual ridging in place. Latest guidance indicates mainly increasing mid/high clouds through midnight with moisture deepening somewhat by daybreak. However models including the HRRR hold back most of the scattered showers across the far northwest until just before 12Z. Thus delayed pops a few hours overnight with low chances by dawn far west and mainly increasing clouds elsewhere. Dropped lows again in spots given only thin cirrus to start and dry air, which combined with less wind in the valleys should allow some 30s overnight with low/mid 40s elsewhere. Previous discussion as of 248 PM EDT Saturday... Going to see increasing clouds late tonight ahead of a weak front. Models are showing limited eastern extent to shower threat late tonight and Sunday as westerly flow will be cause a drying effect to the lee of the Central Appalachians, so maintaining high chance to low likelys over the western slopes of Southeast WV, to slight to low chance pops as far east as the Blue Ridge. Expect temps tonight to stay warmer than Saturday mornings, with lows in the 40s, with possibly some upper 30s in the NC mountains. Sunday will be will be a bit cloudier, especially in the mountains, with some sunshine at times expect east of the Blue Ridge. Temperatures will warm to the lower to mid 50s in the Southeast WV mountains, to upper 50s to around 60 across the mountains, with mid 60s to around 70 from Roanoke east to the piedmonts of VA/NC. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY NIGHT/... As of 300 PM EDT Sunday... A weak mid-level disturbance tracking east in zonal flow is expected to form a surface reflection along a washout frontal boundary draped across North Carolina. Majority of the lift and moisture will reside with the mid-level disturbance, bringing a chance for light rain to areas north of hwy 460 and moderate rain chances north of I-64 Sunday night. Both waves track off the mid Atlantic coast Monday morning. A weak cold front will slowly move across the area Monday behind the exiting disturbance. Light rain showers are possible Monday morning north of hwy 460, then south during the afternoon. A weak shallow wedge of high pressure will follow the front. A warm front aloft will overrun the area Monday night, keeping light rain, drizzle, low clouds and fog in the area into Tuesday. Pressure fall to the north will break the wedge by late afternoon Tuesday. With a frontal passage and a shallow dirty wedge providing abundant cloud cover and rain to the region Sunday night through Monday night, afternoon temperatures will be cooler than normal with overnight temperatures being slight warmer than normal. Areas that see the wedge erode Tuesday, such as the foothills and mountains, should see temperatures warm into the lower 70s. If the wedge holds over the piedmont through the afternoon, temperatures may get stuck in the 60s. However, it looks like the wedge will break before sunset, sending piedmont temperatures into the mid 70s. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... As of 230 PM EDT Sunday... An upper level trough over the Great Lakes will send a strong cold front across the region Wednesday. The GFS has this front quickly moving across the region Wednesday morning. Strong dynamics and elevated PWATS could bring heavy rain into the region, however thunderstorms-severe threat is low with the frontal passage occuring during non-peaking heating hours. The ECM is slower with showers coming across the mountains in the morning, then over the foothills and piedmont in the afternoon. If cloud cover does not impede heating, the chance for thunderstorms and severe weather is elevated east of the Blue Ridge. High pressure builds in behind the front Wednesday night and hangs around through Friday. The next chance for rain will be Saturday with another strong frontal passage. Temperatures will run 5F-10F cooler normal through the period. Wednesday night into Thursday morning, temperatures will drop below freezing. Other nights will remain cool with the possibilities of frost. && .AVIATION /00Z SUNDAY THROUGH THURSDAY/... As of 700 PM EDT Saturday... VFR conditions are expected to prevail tonight into early Sunday under high pressure. A cold front will be approaching the region from the northwest late tonight which will bring high/mid clouds into the area overnight with cigs lowering by Sunday morning. Some small possibilities do exist for stray showers in the mountains overnight into tomorrow morning, however probability is low enough that they will not be advertised in the TAFs at this time. Expect cigs to remain VFR east of the mountains Sunday afternoon but lower to perhaps MVFR levels at KBLF/KLWB by mid to late afternoon. Still appears any showers to remain across the far west but not enough to include mention in the TAFS attm. West to southwest winds may again pick up just ahead and espcly behind the front later Sunday with gusts of 15-25 kts possible mainly along/west of the Blue Ridge. The front will cross the region from the northwest late Sunday into Sunday night. Low pressure riding along the boundary will likely result in sub-VFR cigs and vsbys in rainfall across at least northern sections while KDAN may stay south of the lower cigs/rainfall. There is a chance of snow or mixed winter precipitation just north of KLWB Sunday night where more in the way of IFR may occur. Extended Aviation Discussion... Low clouds, fog, and a few rain showers or drizzle may linger into Monday ahead of a warm front lifting by to the northwest. Tuesday still is questionable but appears improving flying conditions in order behind a passing warm front with any leftover lower cigs/drizzle giving way to VFR under increasing southwest flow by afternoon. Another potent cold front crosses the region Wednesday with widespread sub-VFR in showers likely. A few thunderstorms may also occur with this stronger midweek front. High pressure follows with a return to widespread VFR on Thursday. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...JH NEAR TERM...JH/WP SHORT TERM...RCS LONG TERM...RCS AVIATION...JH/JR/RAB
Area Forecast Discussion
National Weather Service Shreveport LA
932 PM CDT Sat Mar 31 2018 .UPDATE... Weak shortwave energy aloft and an associated cold front at the surface continues to make slow but steady progress south and east across Southern Oklahoma late this evening. There is enough lift aloft and frontal forcing for the development of showers and thunderstorms along this frontal boundary during the last couple hours across Central and Southern Oklahoma extending north and east into Northwest Arkansas. 00z NAM output along with current HRRR suggests that this boundary will continue a slow but steady movement into our extreme northern zones by 12z Sun with the possibility of scattered to numerous showers and thunderstorms moving into these zones later tonight and into the morning hours Sunday. The current forecast has a good handle on this possibility. IR Imagery showing thin high clouds continue to blanket our region this evening with progs showing the development of lower cloud cover encompassing all but our extreme eastern zones after midnight as well. Thus given the pressure gradient in place and the continued southerly winds, do not think temperatures will fall nearly as low as they fell last night. Current forecast suggest another 5-10 degree temperature drop overnight, a little more across our eastern zones which again is in the ballpark. Therefore, no additional changes to the forecast are necessary attm. 13 && .PREV DISCUSSION... /issued 757 PM CDT Sat Mar 31 2018/ AVIATION... For the ArkLaTex VFR with some low and mid clouds over OK movg SE. In addition, overnight stratus is expected toward daybreak and will affect all terminals until mid to late morning. Some showers will edge SE out of OK into near KTXK by 12Z. Light SE winds overnight will pick up to 10KT from S/SW. Climb winds are S/SW 20-30KT to FZL 11.6kft and then W/NW 30-50KT for flight levels. Outlook is for little change into Monday and fropa late Tuesday. /24/ && .PRELIMINARY POINT TEMPS/POPS... SHV 59 78 60 78 / 10 10 20 10 MLU 55 79 57 78 / 10 10 10 10 DEQ 57 71 49 64 / 50 60 50 40 TXK 58 74 53 73 / 20 30 40 20 ELD 56 76 55 75 / 10 10 20 10 TYR 60 79 54 76 / 10 10 30 20 GGG 59 79 59 77 / 10 10 20 20 LFK 60 82 62 79 / 10 10 20 10 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...None. LA...None. OK...None. TX...None. && $$ 24/13