Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/25/17

Area Forecast Discussion...UPDATED
National Weather Service Albuquerque NM
722 PM MST Fri Feb 24 2017 .UPDATE... Updated forecast for tonight to lower overnight temperatures across western and northern NM tonight, especially valleys. Winds have diminished rapidly this evening and likely to decouple completely by midnight. Given very dry airmass in place, temperatures will plummet. 33 && .PREV DISCUSSION...450 PM MST Fri Feb 24 2017... .AVIATION... 00Z TAF CYCLE VFR conditions will prevail during the next 24 hours. West winds will diminish shortly after sunset. West winds will increase at most terminals Saturday afternoon. 33 && .PREV DISCUSSION...255 PM MST Fri Feb 24 2017... .SYNOPSIS... Much colder tonight due to a very dry air mass which has overspread most of New Mexico. A few snow showers may be found over the higher terrain near the Colorado border and northeast plains tonight. Dry with highs below average Saturday and some afternoon breezes in the east, which could lead to critical fire weather conditions over the northeast and east central plains. A moist westerly flow will bring increasing chances for rain and snow showers to mainly the northwest third to half of New Mexico Saturday night through Tuesday but the east should be relatively dry with some afternoon breezes. High temperatures will remain below average during this time and may not recover to near average until late next week. && .DISCUSSION... Dewpoints have really cratered this afternoon with single digits in many areas and a few mid to upper teens in the far northeast where the moisture is relatively more plentiful behind the back door surface boundary. Potentially a few flurries spread over the nrn mts and into the northeast, in line with RAP13 and HRRR which have been fairly persistent with this idea but taper off any minor precipitation later tonight. Due to the drier air mass, low temperatures tonight will be colder, especially over the northwest third by about 5 to 15 degrees and lows overall will be below average. Zonal flow Saturday will be dry with some breezes in the east. Chances for precipitation increase Saturday night and Sunday for portions of the west and central as a weak trough passes overhead. Another such feature is expected Monday through Tuesday, but there looks to be more imported moisture with this second feature, therefore it may be a more prolific snow producer for some of the higher terrain and west facing slopes of the northwest, where at least spotty advisory level snows could accumulate. But neither of these features would be considered a significant storm system by any means. Occasionally breezy to windy conditions will impact the east as well as the higher terrain during this period and overall temperatures will continue to be below average. Mid to late next week appears to be dry, although models continue to have some differences in the formation and location of a closed/cut off to our southwest. Right now the solutions are mostly dry, and we may warm to near average late next week. && .FIRE WEATHER... A progressive pattern through early next week will enhance potential for critical fire weather conditions on several days. A few notable features in this pattern will make for challenging decision making. For today, a back door frontal boundary made it further south and west than indicated yesterday so it has taken a bit longer for the humidity to drop to the 10 to 15% range over the east central plains. The greatest confidence area for critical conditions will be along and south of I-40 east of Santa Rosa where high temps are expected to be near normal with moderate haines values. Farther north and west temps are almost 10F below normal and haines are low. A red flag warning this afternoon over the east central plains will expire this evening as winds decouple. A similar challenge exists for Saturday as winds are shown to veer around to the southwest over much of eastern NM toward mid day. Another round of critical fire conditions is possible over the east central plains and northeast plains Saturday afternoon. Have issued a Fire Weather Watch for zones 104 and 108. Critical fire conditions could expand into eastern portions of zones 103 and 107 as well Saturday. Left it to the overnight shift to decide whether to upgrade to Red Flag since high temperatures remain below normal and Haines indices are low to moderate. Windy conditions will persist into Sunday, however a fast moving upper level trough will bring increasing mid level moisture and in turn increase cloud coverage. This will limit fire weather concerns Sunday. Strong downsloping winds over the east central to northeast plains continue into Monday possibly producing yet another round of critical fire weather conditions. Tuesday will see a rinse and repeat of Sunday with another trough quickly swinging through the region increasing cloud cover and producing modest precip chances mainly over the western half of the state. After Tuesday, the weather pattern quiets down with both the ECM and GFS showing lower winds and a generally stable environment. Ventilation rates decrease considerably on Wednesday and Thursday. Temperatures will rebound to normal to just above normal levels to by mid to late next week. 24 && .ABQ WATCHES/WARNINGS/ADVISORIES... Fire Weather Watch Saturday afternoon for the following zones... NMZ104-108. && $$ 33
Area Forecast Discussion
National Weather Service Caribou ME
1007 PM EST Fri Feb 24 2017 .SYNOPSIS... A weak back door cold front will move southward into Downeast portions of the region overnight and then become stationary early Saturday morning. This front will lift back to the north across all of the region later Saturday morning and afternoon as low pressure tracks northwest of the region Saturday evening. This same low will bring cold front across the area late Saturday night. Canadian high pressure will then build across the region on Sunday. && .NEAR TERM /THROUGH SATURDAY/... 1005 pm update... Temps are dropping acrs nrn Aroostook in wake of bndry that mvd thru this evng. Snow is falling acrs the St. John Vly with sleet occurring further south attm. Temps are still abv frzg south of about a Caribou to Billy-Jack Depot line with a vry slow drop. 00z raob out of CAR indicated from the surface up to 825mb with latest HRRR about a degree too cold with sfc/925 and 850mb temps. RAP was even colder than HRRR and hv adjusted things accordingly as models continue to be too cold for the ovrngt hrs. Thus hv boosted temps up by a degree or so with low temps being reached arnd 06z bfr stabilizing and then rising twd daybreak. This has impacted ptypes tonight with just patchy light frzg rain expected mainly for nrn Aroostook, hwvr colder vly locations in nrn Somerset and nrn Piscataquis may see a light glazing and hv kept frzg rain advisory going for current areas. Next question bcms dense fog for the ovrngt. Dwpt depressions are around zero with locally dense fog from about Bangor over twd the NB border. Coastal zones rmn out of fog with srly flow allowing some mixing to prevent fog dvlpmnt with areas just to the north in dead calm winds. Thus, wl issue dense fog advisory thru 12z. No other chgs needed at this time. Prev discussion blo... Rain is finally ovrsprdng the region late this aftn, but temps both at the sfc and alf up to 850mb are much milder attm then thought 6 to 12 hrs ago. Also, all models have backed off some with regard to how much llvl cold air will move Swrd into the FA behind a weak back door cold front xpctd to settle to Downeast ptns of the region by very erly Sat morn. This resulted in making a difficult decision to canx the fzra adv for zones 10...5 and 6, the N Cntrl ptns of the region, orgnly slated for late tngt into Sat morn. We still believe enough llvl cold air will likely be present later tngt for lgt fzra for NW and far NE ME, but not with 100 percent confidence, so this ptn of the fzra adv remains in effect from 11 pm tngt til 10 am Sat. Any ice accumulation will be msly a tenth of an inch or less ovr the fzra adv area. With most of the first batch of organized ovrrng precip exited N of the FA by daybreak Sat, msly Chc fzra pops in the adv area will be left across the adv area Sat morn with sct shwrs and patchy dz mentioned Swrd to the coast. Fog, which we assigned with sct shwrs and patchy dz, will become more prominent S to N across the region late tngt into Sat as both temps and dwpts rise abv fzg spcly as the front lifts back to the N across the region later Sat morn into the aftn. Fcst hi temps will not be achieved until erly eve given the late day surge of llvl warm air behind the cold front. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... Saturday evening will bring a mild southeasterly breeze ahead of an approaching cold front. Some scattered showers or patchy drizzle are possible during the evening ahead of the front. The cold front will then move across the area around midnight Saturday night bringing a period of rain. Some of the showers may be heavy and there`s a potential for an isolated rumble of thunder. Elevated cape values are up to 300 J/KG as the front pushes through. Showers will move east and away early Sunday morning as colder air pushes in. Some snow showers are likely in the higher elevations to the west early Sunday morning. Colder air will follow on Sunday as low pressure over eastern Canada moves away and high pressure builds onto the east coast. Sunday night will be cold and dry as high pressure moves off the east coast. Clouds will increase late at night ahead of a weak shortwave approaching from southern Quebec. Some snow showers will then be likely across the north late Sunday night into Monday morning as the shortwave and weak secondary cold front slides across the north. Temperatures Monday afternoon will then modify into the mid 30s north and mid 40s Downeast with partial sunshine. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... Monday night into early Tuesday should be mainly dry as high pressure ridges over the region. A weak low with one center racing across southern New England and another center over the great lakes will approach Tuesday afternoon possibly bringing some rain or wet snow Downeast. The main low will approach on Wednesday. Boundary layer temperatures will likely be cold enough for some snow over the north. However, a mix changing to rain will be likely Downeast on Wednesday. The low pushes through and quickly moves away Wednesday night followed by dry weather in high pressure Thursday into Thursday night. Another weak low will move in on Friday bringing a chance for some light snow across the area with the best chances Downeast as the low tracks south of the Gulf of Maine. && .AVIATION /03Z SATURDAY THROUGH WEDNESDAY/... NEAR TERM: Northern terminals expected to bounce back and forth between VFR and MVFR for the first several hours this evening before eventually settling at MVFR after 03z. BGR and BHB will likely be IFR/LIFR through the day Saturday in -DZ, FG and low clouds. Ptypes will be in question north of PQI with -FZRA expected after 03z, possibly mixing with PL early. Expect IFR conditions during the day Sat. Northern zones will likely see LLWS at FL020 toward end of TAF valid time from 19040kt. SHORT TERM: IFR conditions in low clouds, rain and fog are likely Saturday night. Conditions should improve to VFR Downeast early Sunday morning then improve to VFR across the north mid morning Sunday. VFR conditions across the north Sunday night will lower to MVFR over the north late Sunday night and remain VFR Downeast. VFR conditions Downeast and MVFR conditions across the north are likely on Monday. && .MARINE... NEAR TERM: No headlines will be needed tngt and Sat...with winds and seas increasing Sat aftn to near SCA thresholds by erly eve. Marine fog will likely present spcly late tngt into Sat morn. SHORT TERM: An SCA will likely be needed Saturday night into Sunday for gusts up to 30 kt in S winds ahead an approaching cold front. The SCA will likely have to continue for gusty westerly winds following the front on Sunday. && .HYDROLOGY... No changes to the Flood Watch were made with this forecast cycle. Snow melt from the deep snowpack continues tonight through Saturday night with rainfall amounts of just over a half inch by Sunday morning. Water levels are starting to rise modestly on the river gauges on the Piscataquis and its branches, but the best response should be later Saturday night into Sunday. NERFC and ensemble river forecasts continue to rises into Sunday morning, but nothing that generates strong concerns at this point. The focus will remain on the southern half of the forecast area where temperatures will stay above freezing into Sunday and where more melting has already occurred with this thaw. Localized ice movement followed by jams is the scenario to watch...mostly for southern Piscataquis and Penobscot basins. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...Freezing Rain Advisory until 10 AM EST Saturday for MEZ001>004. Flood Watch from 7 AM EST Saturday through Sunday evening for MEZ010-011-015>017-031-032. MARINE...None. && $$ Near Term...Farrar/VJN Short Term...Bloomer Long Term...Bloomer Aviation...Farrar/VJN/Bloomer Marine...Farrar/VJN/Bloomer Hydrology...
Area Forecast Discussion
National Weather Service Cheyenne WY
836 PM MST Fri Feb 24 2017 .UPDATE... Issued at 836 PM MST Fri Feb 24 2017 The recent snowfall will provide plentiful moisture and with very cold temperatures tonight, freezing fog will develop across the North Platte River Valley. Freezing fog has already begun to develop at Alliance bringing visibility down to 1/2 mile. Based on the latest hrrr guidance fog for the rest of the North Platte River Valley beginning around 6Z. All areas will begin to dissipate by 12Z tomorrow morning. && .SHORT TERM...(This evening through Saturday) Issued at 243 PM MST Fri Feb 24 2017 Forecast concerns in the short term deal with winds and blowing snow. Currently...Still getting some wrap around moisture from the storm system that moved through the area yesterday and last night. Light snow echoes being observed on radar mainly east of the Laramie Range. Aerial coverage is shrinking, so do not think we will have any more concerns with snow this afternoon. Allowed all headlines to expire from the winter storm at 11AM today. Attention turns to tonight as westerly winds return. GFS 700mb winds increase to 30kts by 06Z and over 40kts by 12Z Saturday morning. Local high wind guidance showing Craig to Casper 850/700mb height gradients increasing to the mid 40s after 06Z tonight. WRKGHT guidance slightly higher with close to 50mtrs. Lots of loose snow out there across the wind prone areas. Thought it prudent to issue a Blowing Snow Advisory for the wind prone areas. One thing the evening and night crew to keep an eye on is strength of wind. Did go over guidance on winds for the wind prone areas by 10-15 knots. May need to go higher on the overnight forecast. If we get much higher, we may need to upgrade the advisories to maybe a ground blizzard warning for the wind prone areas. Advisories may need to be expanded Saturday after sunrise as soundings showing 35kts mixing down at Cheyenne, Laramie and Rawlins. .LONG TERM...(Saturday night through Friday) Issued at 243 PM MST Fri Feb 24 2017 Dry but still chilly Sunday with most locations not going above freezing except for maybe the southern Nebraska Panhandle for afternoon highs. We start a gradual warmup Monday as the surface to midlevel flow goes more west to southwesterly ahead of an approaching shortwave that will cross the area late Monday into Tuesday. That next shortwave brings our next chance for snow in across our western areas Monday into Tuesday, with midlevel winds 40 to 50 kts setting the stage for more mountain snow. If stronger midlevel winds pan out as some model guidance suggests, we could see a foot of new snow in the Sierra Madre Range with less than that in the shadowed Snowies. Although not as windy as what we are expecting for Saturday, the wind prone areas of SE Wyoming will see wind gusts 40 to 50 mph just about each day with perhaps Tuesday into Wednesday being a little stronger. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 508 PM MST Fri Feb 24 2017 Occasional MVFR cigs will continue through sunset, then should trend up to VFR through the remainder of the evening. One concern for tonight will be fog formation in the Laramie Valley including KLAR and river valleys across the panhandle tonight including KCDR, KBFF and KAIA. Latest high resolution guidance shows fog developing near these locations, with highest confidence at KBFF and KAIA. Added mention of either VCFG or prevailing IFR fog at all four locations during the overnight period. Blowing snow could then be an issue due to winds 20G35kt tomorrow for KCYS, KLAR and KRWL, but right now it looks like the stronger winds won`t mix down until after the boundary layer inversion breaks around 18Z or shortly thereafter. && .FIRE WEATHER... Issued at 243 PM MST Fri Feb 24 2017 Widespread snow pack will keep fire weather concerns in check across southeast Wyoming and Nebraska Panhandle through the weekend. Cold daytime highs will aid in slow snowmelt, so snowpack could persist into the middle of next week. No fire weather concerns expected at least through Wednesday next week. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...Winter Weather Advisory until 5 PM MST Saturday for WYZ106-110- 116-117. NE...None. && $$ UPDATE...RJM SHORT TERM...GCC LONG TERM...JG AVIATION...RJM FIRE WEATHER...GCC
Area Forecast Discussion
National Weather Service Quad Cities IA IL
558 PM CST Fri Feb 24 2017 ...AVIATION UPDATE... .SYNOPSIS... Issued at 332 PM CST Fri Feb 24 2017 20z surface observations showed a 996mb surface low pressure located across northern Illinois and Indiana. Cold northerly winds produced temperatures ranging from the lower 30s over Independence to lower 40s over Macomb and Princeton. A 500 mb vort max associated with the trailing upper level low over western IA and an associated deformation zone helped to spawn widespread wintry precipiation across much of central Iowa. This vort max was slowly moving to the east and will serve as the main weather producer in the short term. && .SHORT TERM...(This Evening through Saturday) ISSUED AT 332 PM CST Fri Feb 24 2017 Clear slot across the area will pull to the east as the deformation zone associated with the surface low moves to the east today and tonight. Main forecast concern will be snowfall amounts and the diminishing trend of the precipitation. Actual track and strength of the sfc low was further south and lower than previously expected. As a result the onset of snow has been delayed across much of the area until 00z Saturday. Freezing drizzle has occurred across most of the advisory area. As colder temperatures and more moisture overtakes the clear slot this freezing rain will transition into snow. Guidance has come down in overall QPF amounts from this system. The HRRR is the less aggressive of all the guidance and suggests about an inch in overall snowfall for the northern zones. The rest of the model suite has the northern zones getting 2 to 4 inches. Our forecast of 1 to 3 inches across northern zones in the winter weather advisory. Tomorrow should be free of precip, could see some patchy drifting snow from the winds, otherwise, main impacts would be slick roads due to moisture on the roads and the drop of temps into the 20s and teens. .LONG TERM...(Saturday Night through Friday) ISSUED AT 332 PM CST Fri Feb 24 2017 Flow pattern aloft turns zonal to southwest through the first half of next week ushering in warmer air, with temperatures moderating back above normal with highs mainly in the 40s/50s. A series of waves will move through the flow accompanied by precipitation chances. Very low precip chance for Sunday with onset of WAA and initial low amplitude wave, but moisture is rather meager. Any precip should it occur would be sprinkles or light rain, but mostly virga which could lead to cooler highs than currently forecast for Sunday. Better signal and subsequent precip chances appear to be for Tuesday as a stronger wave moves across the Upper Midwest and Great Lakes. Given this more northerly track consensus from the models I have kept the precip type mainly rain, with just a mention of snow Monday night in lead WAA precip potential. In the wake of the Tuesday system the flow pattern turns northwesterly for mid to late week. A series of Clipper systems are shown by the models, one around Thursday and another around Saturday. Both these systems are shown to pass mainly to our northeast at this time, thus precip chances appear small as the area will largely reside in dry warm sector with moisture starved cold frontal passages. Will see up/down temps during this time favoring above normal in warm sector ahead of systems then cooling back near to a little below normal in the wake. && .AVIATION...(For the 00Z TAFS through 00Z Saturday Evening) ISSUED AT 550 PM CST Fri Feb 24 2017 An area of light snow will move across the terminals producing IFR/MVFR conditions with lower conditions with heavier snow at CID/DBQ. After 25/05Z...snow will lessen to flurries or end with MVFR conditions until around sunrise. Skies will become clear or mostly clear by mid day. Northwest winds of 15 to 25 MPH will begin to decrease by late afternoon on Saturday. && .HYDROLOGY... Issued at 332 PM CST Fri Feb 24 2017 Rainfall in the past 24 hours along with routed flow north of the area will lead to rises on area streams and rivers. In general though heavy rainfall was not as widespread, thus the main trend today is for most crests in next 7 days being lowered by 1/2 to over a foot from those forecasts issued yesterday and many areas seeing only within bank rises. This is the case on the Iowa River at Marengo, which is now staying below FS and therefore cancelled the Flood Watch. One exception is on the Cedar River, where the recent rainfall combined with above normal flows has actually led to higher confidence on minor flooding near Conesville. As a result, I have upgraded the Flood Watch to a Flood Warning as it is shown to rise above FS within the next 24 hours cresting by early next week. On the Mississippi River, the recent rainfall along with routed flows will lead to rises over the next 7 days, with several sites shown to reach or exceed flood stage toward the end of the 7 day period. However, confidence is low given the noticeable lowering trends past 24 hrs and uncertainties in snowmelt and amount of routed water north of the area. As a result, no Flood Watches for the Mississippi at this time, but can`t rule out eventual watches and possibly a few warnings in the next 7-14 days depending on snowmelt and routed water. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...Winter Weather Advisory until 6 AM CST Saturday for Benton- Buchanan-Delaware-Dubuque-Jones-Linn. IL...NONE. MO...NONE. && $$ SYNOPSIS...Speck SHORT TERM...Gibbs LONG TERM...McClure AVIATION...Nichols HYDROLOGY...McClure
National Weather Service Jackson KY
949 PM EST Fri Feb 24 2017 .UPDATE... Issued at 949 PM EST FRI FEB 24 2017 Current conditions feature the area of showers and storms at the CWA doorstep along the I-75 corridor. It seems that no dominant cold pool or organization of the cells in central Kentucky, or Tennessee for that matter has occurred. Thus, with the cap still in place over eastern Kentucky, will be hard pressed to see any severe convection tonight. So have updated to pull the severe wording from the forecast but have left in the mention of strong storms with the potential to produce gusty winds and small hail. Have updated the HWO as well to take out the severe wording and input the mention of strong storms. UPDATE Issued at 713 PM EST FRI FEB 24 2017 Current conditions feature a line of showers and segments of strong to severe thunderstorms in central Kentucky to the west tracking northeast. Fine tuned the pops to account for a more timely arrival into eastern Kentucky. Decided to keep the severe mention in the forecast though, with heating lost and instability becoming more elevated, the cap in place more and more hints at any severe weather in eastern Kentucky will be dependent on what develops in central Kentucky and advects in. Mainly in the form of a squall line or bowing segments. As well, the main threat continues to be damaging winds. Onset into Kentucky may be as soon as 9pm. A new ZFP was sent out to account for these changes. && .SHORT TERM...(This evening through Saturday night) Issued at 517 PM EST FRI FEB 24 2017 South-southwest flow aloft will become more westerly through the short term as a potent storm system plows through the Great Lakes, pulling a trough through the Commonwealth over the next 24 hours. Surface low pressure over Lake Michigan will continue to move off to the northeast, pulling a cold front eastward through the region, and into eastern Kentucky during the overnight. A line of thunderstorms currently developing across the Midwest will move into our forecast area through the overnight period. HRRR timing of the main line of convection has been fairly consistent and generally agrees with what has been advertised. Some thunderstorms could produce severe weather with the main threat being damaging winds. Hail will be a secondary threat and a brief, isolated tornado can not be ruled out. Moisture, or the lack thereof will be the primary limiting factor to severe weather as dew points will top out in the mid 50s ahead of the front. Timing of the cold front through eastern Kentucky will also be a limiting factor. Regardless bulk shear is very impressive with this system, 40-70 kts, with the majority of the shear realized in the lowest 3 km. Thus the potential for bowing cells and line segments will be favored. Surface based instability to support this storm mode is not ideal but does appear to be sufficient. Consequently damaging winds are the primary severe weather threat. This has a distinctive QLCS flavor to it and considering the environment as a whole feel an isolated tornado can not be ruled out, though features of this type tend to be weaker than most and short lived. Low wet bulb temperatures and freezing levels suggest hail will be a possibility as well. Colder air invades the coal fields on Saturday and will set things up for a rather chilly weekend in general. Gusty winds will combine with strong cold air advection to make for a less than optimal day for outdoor activities. .LONG TERM...(Sunday through Friday) Issued at 315 PM EST FRI FEB 24 2017 The extended portion of the forecast will be fairly active, with alternating periods of wet and dry weather and warm and cooler conditions. The period will likely start off dry, with slightly above normal temperatures Sunday and Sunday night. The pattern is then expected to shift on Monday, as a weak warm front moves through the area, bringing persistent southerly flow and warmer air into the region. Rain showers should begin to move into the area from the southwest and west late Sunday night into early Monday morning. The rain will overspread the entire area by late Monday afternoon and early Monday evening, as an area of low pressure moves along what will become a nearly stalled out frontal boundary. This pattern is tentatively expected to persist through late in the day on Tuesday. A wave of low pressure is then forecast to form along the western end of the stalled front Tuesday night. This second area of low pressure is then expected to push eastward on Wednesday, and will drag another cold front across the lower Ohio valley and Tennessee valley regions. This boundary may be just strong enough, and just enough moisture an instability available, for a few thunderstorms to form along and just ahead of the front, as it moves across the region. Once the front moves past us Wednesday night, any thunderstorms should give way to all rain showers. We may even see enough cold air filter in behind the system to allow some snow to mix in with whatever rain is left. The last of this precipitation should be out of the area by late Thursday morning. Thursday and Thursday night should be mostly dry. There is an outside chance that a few rain and snow showers will move across the area along and north of I64 to end the period, with due to uncertainty, this should be taken with a grain of salt. Temperatures in the extended on average will be above average each day, with the warmest days being Monday, Tuesday, and Wednesday, when the highs will be in the 50s and 60s. Closer to normal values should be experienced on Thursday, when the mercury is forecast to max out lower 50s. Nightly lows should be in 30s, 40s, and 50s. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) ISSUED AT 713 PM EST FRI FEB 24 2017 Onset of showers and severe thunderstorms will be around 01z across eastern Kentucky and pushing east through 05z. Have updated the TAFs to account for this timing. MVFR to IFR visibility due to the moderate rainfall will be the impacts. a few MVFR cigs will be possibly but most cigs will remain above 3 KFT. Winds will continue to be southwesterly gusting to 25 knots at times. Winds are expected to then increase again tomorrow afternoon with westerly winds gusting up to 25 knots as well. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...SHALLENBERGER SHORT TERM...RAY LONG TERM...AR AVIATION...SHALLENBERGER
Area Forecast Discussion
National Weather Service Memphis TN
723 PM CST Fri Feb 24 2017 .UPDATE... Updated to expand slight chance for thunder. && .DISCUSSION... Tasil end of front generating a few storms acros portions of Central Mississippi. This lightning activity will likely move into Tallahatchie and Yalobusha counties over the next hour. expanded threat for storms into this region. JAB && .PREV DISCUSSION... /issued 620 PM CST Fri Feb 24 2017/ UPDATE..Updated to lower evening PoPs in the east. DISCUSSION... Cold front pushing into West Tennessee this hour...with very isolated shower activity associated with it. As temperatures fall this evening decreasing instability should keep rain chances lower than current thinking across the east through midnight. The threat for a strong storm along the Tennessee River Valley is also quickly waning...with an update to the HWO likely needed in the next hour or two. Adjusted the evening forecast accordingly. All other forecast parameters are currently on track. JAB PREV DISCUSSION... /issued 557 PM CST Fri Feb 24 2017/ UPDATE... Updated for the 00z Aviation Discussion. PREV DISCUSSION... /issued 338 PM CST Fri Feb 24 2017/ At 3PM...A cold front is currently situated just west and nearly parallel to the Mississippi River. WSR-88D radar trends continue to show light rain showers along and north of the forecast area with just a few along the front. Water vapor imagery shows a positively tilted shortwave over Iowa at this hour, with severe thunderstorm watches stacked downstream across much of Indiana where the best dynamics remain. For our area, moisture and instability continues to be limited ahead of the front, as evidenced by high temperatures only in the 60s over much of the area. In addition, the latest AMDAR soundings from Memphis International Airport also indicate a stout capping inversion from 850 to 700mb. The latest HRRR run indicates that best chances for rain and thunderstorms will be across west Tennessee and northeast Mississippi through about 10 PM tonight. A few storms could be strong near Henry and Benton County, Tennessee where the best forcing for ascent will be. Elsewhere, showers and some elevated thunder will be possible as the front pushes quickly across the area tonight. Cool Canadian high pressure will build into the region on Saturday with temperatures remaining only in the upper 40s and lower 50s during the day. The surface high will become nearly centered over the Mid-South by Sunday morning, resulting in optimum radiational cooling. Guidance continues to trend cooler with low temperatures, and most places will drop below the freezing mark for the first time in over a week. A warming trend will begin again on Sunday as high pressure slides eastward, and winds turn around to the south. Both main synoptic models continue to show a shortwave kicking off a few showers after midnight Sunday and overspreading the entire area by Monday morning. A broad surface low is expected to develop over the Central Plains and push a warm front northward through our area during the day on Monday. As it lifts, showers and thunderstorms will be possible much of the day. The aforementioned surface low will traverse to the great lakes during the day on Tuesday and drag a cold front into our area by late Tuesday night. The models continue to diverge past this point, with the GFS pushing the front all the way through our area by Wednesday morning keeping us dry for the day, whereas, the Euro keeps it nearly stationary as a weak surface low rides along the front. Thus, the Euro keeps us in a wet and unstable airmass all day on Wednesday, contrary to the dry GFS solution. The GFS continues to be the outlier, with respect to evolution of the upper level flow. Thursday into next weekend continues to be dry at this point, as zonal flow and slight upper level ridging remain in place over the Mid-South. Temperatures look to return to seasonal readings with highs near 60 and lows in the 40s. AC3 && .AVIATION...00z TAFs VFR conditions will prevail through the period. A few showers and maybe a thunderstorm near KTUP this evening can be expected as a cold front moves through the region. Gusty southwest winds will veer northwesterly behind the front with continued gusts. This should persist through midday Saturday before gradually diminishing. Skies will clear at all sites later this evening. JLH && .MEG WATCHES/WARNINGS/ADVISORIES... AR...None. MO...None. MS...None. TN...None. && $$
Area Forecast Discussion
National Weather Service Nashville TN
900 PM CST Fri Feb 24 2017 .UPDATE... FOR EVENING DISCUSSION. && .DISCUSSION... Forecast is really on track this evening. We`ve been monitoring convective activity on what seems to be a pre-frontal trough over the last couple of hours. A couple of cores have peaked out at decent heights, but with dew points in the low to mid 50s ahead of this trough, we`re not getting the surface based instability to really help spike these storms at anything more than "strong". Pea and dime-sized hail is the largest report we`ve had since the beginning of the convection. That`s not to say one or two couldn`t become severe over the next few hours, but our potential for anything widespread is really looking low right now. Biggest threats through the remainder of the evening will continue to be damaging gusty winds and large hail as the 00Z sounding from OHX showed 500 mb temperatures around -18 degrees C and relatively steep mid-level lapse rates. The interesting element in all of this is the lack of consistency between some of our models regarding any development on the front itself over the next several hours. The HRRR has had the majority of the development on this pre-frontal trough, where the NAM shows the development on the front itself, which is currently back over W Tennessee, nearing Clarksville. With the limited instability, I still think the best money is on this pre-frontal trough for any severe potential this evening. && .AVIATION... 00Z TAF DISCUSSION. Chances for showers and thunderstorms will move in this evening from west to east, and look to impact all terminals. Looking at short term model consensus, KCKV looks to see showers and VCSH from around 00Z through 05Z, KBNA from 02Z through 06Z, and KCSV from 03Z through 07Z. Current thinking is thunderstorms will mainly impact KBNA and KCSV, and will bring chances for MVFR/IFR vis and MVFR cigs during thunderstorm passage for KBNA around 02Z-05Z and for KCSV from 05Z-08Z. After the cold front passes, winds will flip to the northwest and remain around 10 to 15 knots sustained with gusts to around 20 knots. Some models are placing MVFR cigs again during the morning hours after sunrise, but left out mention for now in the TAF until short term models remain consistent with the MVFR cig solution. && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ DISCUSSION......Unger AVIATION........Barnwell
Area Forecast Discussion
National Weather Service Charleston WV
1018 PM EST Fri Feb 24 2017 .SYNOPSIS... A strong cold front crosses pre- and post- dawn Saturday morning, followed by cooler weather for the weekend. A couple systems next week with precipitation chances. && .NEAR TERM /THROUGH SATURDAY/... As of 1010 PM Friday... Prefrontal line of strong storms poised to cross into our southeast Ohio counties in the next 1 to 2 hours. Much of the activity over the last few hours has been strong to only marginally severe. The prospects for severe wx thankfully appear to be waning overnight with southeast Ohio standing the best chance for some damaging wind gusts in bowing segments within the line. As of 645 PM Friday... See latest PNS/RER for info today`s records, February all time records, and all time record meteorological winter highs. Forecast generally in good shape. I tweaked hourly pops using latest HRRR as an aid. There is still a concern for locally damaging wind gusts after midnight across southeast Ohio, northeast Kentucky and western West Virginia. The mid level capping currently in place will erode overnight with the approach of the front. With steepening low level lapse rates along with the low dewpoint spreads in place...concern exist for a congealing QLCS bringing down strong downdrafts. As of 315 PM Friday... After a record breaking warm afternoon and a dry, mild evening, a strong cold front still appears on track to bring a line of showers and thunderstorms through the area just ahead of it overnight into Saturday morning. The main convective threat is wind damage as super cells that form upstream evolve into a fast moving squall line, but the hail and even tornado threat could not be entirely ruled out if the low level shear can give rise to sufficient mesoscale organization. Dry slot behind the cold front will bring a quick end to the showers and thunderstorms from west to east on Saturday, but wrap around precipitation will then spread into northern portions of the area later Saturday afternoon. These rain showers will start turning over to snow showers late, as much colder air advects in. Used a blend of primarily near term sources for hourly temperatures in the warm air ahead of the front tonight, and in the cold advection behind the front on Saturday. Lows tonight will be close to or equal to highs Saturday. && .SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY/... As of 330 PM Friday... Cold air advection on W/NW flow will bring the chance for upslope snow showers across the mountains through early Sunday morning. Moisture is limited so accumulations will be very light with generally less than an inch. High pressure builds over the area on Sunday and although we remain dry it will be cool relatively speaking. High pressure should hold through most of the day Monday, however a southern stream system will approach Monday evening and showers enter SW West Virginia by 00Z Tuesday out ahead of a warm front. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... As of 335 PM Friday... Zonal flow aloft will make for a progressive and active pattern next week. Our first system brings showers Monday night into Tuesday. The next system will arrive mid week as low pressure tracking across the Great Lakes drag a cold front through the region. Behind this colder air arrives again on NW flow and this will bring a chance for snow showers across the mountains towards the end of the work week. && .AVIATION /03Z SATURDAY THROUGH WEDNESDAY/... As of 645 PM Friday... A strong cold front will impact the area overnight tonight into early Saturday morning. A line of strong showers and thunderstorms just ahead of the cold front is timed to reach HTS near 08Z, PKB 09Z, CRW 10Z, CKB,EKN, and BKW around 11Z. Inserted tempo groups for HTS/PKB where 9 hour policy allows for IFR TSRA with wind gusts to 40 kts. I covered the remainder of the sites with 1 to 2 hour prevailing conditions of IFR gusty showers. Some of the winds may approach severe limits across HTS/PKB/CRW. Conditions will improve to VFR across the lowlands Saturday, as dry air and a rising frontal inversion increases mixing heights to about 5-6 kft. South to southwest surface flow will be gusty at times ahead of the cold front, shifting to west and remaining gusty behind the cold front early Saturday morning. Moderate south to southwest flow aloft ahead of the cold front into tonight will become moderate west behind the cold front on Saturday. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z SUNDAY... FORECAST CONFIDENCE: Medium to high. ALTERNATE SCENARIOS: May need to add TSRA to prevailing for remainder taf sites. Gusty winds will tend to vary, especially with the convection and the passage of the cold front overnight tonight into Saturday morning. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. DATE SAT 02/25/17 UTC 1HRLY 03 04 05 06 07 08 09 10 11 12 13 14 EST 1HRLY 22 23 00 01 02 03 04 05 06 07 08 09 CRW CONSISTENCY H H H H H H H M M H H L HTS CONSISTENCY H H H M H M M H H H H M BKW CONSISTENCY H H H H H H H H M L L L EKN CONSISTENCY H H H H H H H H H H M L PKB CONSISTENCY H H H H H H L H H H H M CKB CONSISTENCY H H H H H H H H H H H M AFTER 00Z SUNDAY... No widespread IFR conditions are expected at this time. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...None. OH...None. KY...None. VA...None. && $$ SYNOPSIS...TRM/MPK NEAR TERM...TRM/30 SHORT TERM...MPK LONG TERM...MPK AVIATION...30