Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 12/10/16

Area Forecast Discussion...Updated
National Weather Service Billings MT
757 PM MST Fri Dec 9 2016 .UPDATE... Further adjustments to highlites with this update. Added the Bighorn mountains and northern/eastern Carbon county to the going Winter Weather Advisories. Radar has shown a pretty strong snow band from Cooney reservoir east through Fromberg and Bridger over the past hour or so. Models fill this area in with snow overnight so expect poor travel on US212 all the way from Red Lodge into Laurel tonight. For the Bighorns the westerly flow pattern isn`t a great snow producer, but this atmospheric river pattern should have enough moisture to overcome the inherent downslope off the mountains to the west. In addition expect gusty winds to create some significant blowing and drifting issues overnight into tomorrow morning. So issued advisory for 4 to 6 inches of snow combined with blowing and drifting snow problems along US14 over the Bighorns. Updated precipitation chances to categorical values generally west of a Hysham to Sheridan line. 00z NAM and HRRR have been increasing precipitation amounts over this area and radar supports this trend. Have a bit of a concern about the area right along the northern Beartooth foothills where radar has been showing a good downslope shadow so far. Its possible that this feature will persist tonight and that snow band currently setting up from Fishtail to Cooney reservoir and Bridger will be the main precipitation producer leaving Red Lodge and Nye with just a dusting. Still seeing some decent dynamics aloft to support some snow though along with some slop over from the upslope into the Cooke City area so kept high pops but lowered snow amounts right along this area, and further lowering may be needed if this downslope signature persists. Latest NAM and HRRR showing axis of best snow from Livingston to Billings overnight into tomorrow afternoon. Already snowing moderately at times in Livingston. Radar has shown snow in the vicinity of Billings the past hour or so and expect snow to get going in central areas in the next hour or so. Heaviest accumulations for western areas is from now through sunrise, central zones from midnight through late morning. Temperatures over western zones are near their lows already and should see a gradual rise overnight. Areas at 6000 feet are currently in the single digits there but climb to 7500 feet and temps are in the mid 20s. May see a few degrees of cooling in central zones thanks mainly to evaporative cooling as snow develops, then a rise by sunrise into the teens in many areas. Eastern zones will stay mainly in the single digits above and below zero with a few teens below around Fallon county. Chambers && .SHORT TERM...valid for Sat and Sun... The first wave of energy is still lingering across Musselshell, Treasure, and Rosebud counties. The next impulse of energy is working into western Montana. As this wave moves into the area, expect snow to spread across the area overnight. Lower elevations will see an additional 1 to 2 inches of accumulation through tomorrow afternoon. The foothills will see 3 to 4 with the high mountains getting up to 6 to 10. This will result in roads continuing to be snowpacked, especially the less traveled roads. Given the accumulations and the snow cover on roads, will continue the Winter Weathe Advisory through tomorrow afternoon. Through the day tomorrow, warmer west winds will begin to shift east towards Billings. As it does, expect the snow to decrease and temperatures to increase into the 20s. Sunday should be drier and warmer. Much of the area will see temperatures in the 20s to near 30. Reimer .LONG TERM...valid for Mon...Tue...Wed...Thu...Fri... Not a lot of changes were made to the extended forecast. Uncertainty is still very high in the global models after Tuesday morning. While the details of the forecast (especially snowfall) are very cloudy right now, it does appear the trend of cold temperatures will continue through next week. Extended begins with another arctic cold front pushing south through the forecast area early Monday. A good feed of pacific moisture in the westerly flow aloft will setup a good overrunning situation (moisture forced to rise over the wedge of arctic air) and give the region another good shot of snowfall around 1-2 inches (2-4 in the mountains) beginning Monday morning. Snowfall will taper off overnight Monday into Tuesday morning. After a mostly quiet Tuesday (expect for some mountain snowfall), big differences in the models begin to appear. The source of these differences arise from the handling of a cut- off upper level low off the Western US, and its interaction with a large upper level low over northern Canada. The GFS and Canadian keep the pacific low weaker, and allow a drier northwest flow to preside over the region through at least Thursday night. The EC solution has a stronger cut-off low in the Pacific, and a weaker upper level low in Canada, this setup results in wetter westerly flow over the region, and allows much better chances for snow late Wednesday night into Thursday. While the details are sketchy at this point, it certainly lent at least a mention of snow in the forecast for Thursday based on these differences. Looking to the end of next week and into next weekend, the global models indicated another disturbance crossing the region, and another shot of snow. Timing differences are quite large with this system however. EC gets the snow going again on Friday while the GFS and Canadian are much slower. Either way, the extended period continues to look unsettled and cold. This is supported well by the model ensembles. Dobbs && .AVIATION... Snow will continue to overspread the region this evening and overnight into Saturday bringing generally MVFR to IFR conditions with LIFR possible under the heaviest snow. Mountain obscurations will be prevalent through the TAF period and MVFR/IFR conditions wont improve to VFR until after 12z, and from west to east. KMLS and KSHR should stay VFR through this system, though isolated MVFR in a quick snow shower is certainly possible Saturday morning. Dobbs/STP && .PRELIMINARY POINT TEMP/POPS... Sat Sun Mon Tue Wed Thu Fri ----------------------------------------------------------- BIL 004/022 012/030 006/010 901/011 902/014 901/013 902/006 +8/S 31/B 25/J 41/B 10/U 12/J 33/J LVM 006/033 017/031 014/020 003/014 902/014 002/015 901/003 +8/S 42/S 35/J 42/J 11/U 12/J 33/J HDN 003/023 009/030 007/012 903/013 907/014 905/014 904/007 88/S 41/B 24/J 21/B 10/U 01/B 33/J MLS 902/013 001/022 002/004 905/011 904/012 904/012 905/006 45/S 31/B 34/J 21/B 10/U 01/B 33/J 4BQ 901/020 006/027 005/010 904/012 903/013 902/014 902/007 33/S 41/B 13/J 21/B 10/U 01/B 33/J BHK 909/008 902/017 902/001 907/007 904/006 906/006 906/001 24/S 41/B 24/J 11/B 11/B 01/B 23/J SHR 008/028 014/030 011/015 903/009 905/012 902/014 904/005 33/S 52/S 24/J 32/J 10/U 01/B 33/J && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...Winter Weather Advisory in effect until noon MST Saturday FOR ZONES 28-29-34-35-39>42-56-63>66. Winter Storm Warning in effect until 6 PM MST Saturday FOR ZONE 67. WY...Winter Weather Advisory in effect until 6 PM MST Saturday FOR ZONE 98. && $$
Area Forecast Discussion
National Weather Service State College PA
1012 PM EST Fri Dec 9 2016 .SYNOPSIS... In the mean the next 8 days will be dominated by an upper level trough. The initial trough will move to our east this weekend as will the massive cold surface high. A wave to our west will bring snow and a wintry mix to the region Sunday into Monday ahead of a weak cold front. By midweek another surge of arctic air will approach the region. This system will likely bring some snow and potentially one of the coldest air masses to invade our region since the winter of 2015. The 850 mb temperatures could be in the -20C range by Thursday and Friday. Next week could end on a frigid note. && .NEAR TERM /UNTIL 7 AM SATURDAY MORNING/... Another update for all elements. Most areas will remain cloudy to mostly cloudy. Radar shows snow bands over central areas weakening. Band that came through our office gave us a dusting. Most of the accumulating snow will be in the northwest. The HRRR keeps snow in Warren County overnight with the potential in the extreme northwestern part of the county for another 4-8 inches of snow before all is said and done. Grids were nudged with HRRR QPF to get numbers close to this. The blends were much lower than the HRRR. Overall a cold night. Snow showers mainly in northwestern areas and some lighter snow in central and southwestern mountains. Most accumulating snows in northwestern areas closer to the lake. Overnight lows mainly teens and 20s. && .SHORT TERM /7 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/... The HRRR was used to show the snow lingering into the day and the total snow is likely 4-8 as stated above. Most of this should fall before 7 AM Saturday morning. Perhaps 1-3 will fall in this period as things wind down. To the south and east a quieter and sunnier day. Still quite cold. Most areas will be several degrees warmer than Friday was and there will be less wind. Always a plus when the wind is light. && .LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/... We modified the Sunday into Sunday night forecast with the new guidance. This produced faster onset of the warm advection induced snow. Some models are very fast with light snow in western areas before sunrise Sunday. We blended the superblend and some slower guidance to compromise. But snow will spread west to east Sunday. It gets really complicated as nearly all forecast systems show some accumulating snow potential but, all show the surge of the 850 hPa 0C line into southwestern PA Sunday afternoon/evening and into north-central areas overnight Sunday around midnight or so. It is possible northwestern areas will never get that warm. Thus had to show mixing snow to ice pellets in southwest and then southeast. Could be some freezing rain. It is too early to get to specific as there is considerable uncertainty. But at this time it is sufficient to acknowledge the potential of snow likely changing to a wintry mix and probably all rain in the southeast early Monday. The cold air comes in during the day Monday into Monday evening to change lingering rain and wintry mix to snow as it winds down. Temperatures behind the front Monday into Tuesday are close to seasonal. A bit cooler than normal temps indicated early next week, but longer range models indicate a significant cold front passage Wed with noticeably below normal temps filtering in for the rest of next week. Ahead of the arctic surge expected later in the week there could be another QPF event. Potentially mostly snow in central and western areas. But the GEFS shows some -18 to -20C air at 850 hPa with the cold front. About 3-5C colder than the airmass we had come through today. && .AVIATION /03Z SATURDAY THROUGH WEDNESDAY/... Bands of lake effect snow showers will continue overnight into Saturday morning. Conditions will improve during the afternoon, as warming aloft occurs and winds shift more to the west and southwest. As of 6 PM, still an band of heavier snow showers from near BFD to just southwest of IPT. Expect a wide range of conditions overnight at BFD and JST. UNV and AOO should be VFR for much of the period. VFR conditions expected at IPT, MDT, and LNS. Earlier discussion below. Low pressure tracking from the lee of the Rockies to the Ohio Valley will bring a broad area of snow/rain to the area Sunday into early Monday. Outlook... Sun-Mon...Widespread MVFR/IFR in snow/rain. Becoming breezy Monday night with snow showers over the wrn 1/3. Tue...Mainly VFR. Wed...More snow showers possible. && .CTP WATCHES/WARNINGS/ADVISORIES... Lake Effect Snow Advisory until noon EST Saturday for PAZ005. Lake Effect Snow Warning until noon EST Saturday for PAZ004. && $$ SYNOPSIS...Grumm NEAR TERM...Grumm SHORT TERM...Grumm LONG TERM...Grumm/RXR AVIATION...Martin
Area Forecast Discussion
National Weather Service Wichita KS
834 PM CST Fri Dec 9 2016 .UPDATE... Issued at 831 PM CST Fri Dec 9 2016 Updated to increase cloud cover tonight and especially Sat and to increase mins over se KS. Short term models have been fairly consistent in lifting another swath of low clouds north across the area Sat morning and leaving them in place through at least mid afternoon. So went ahead and increased cloud cover for mainly the 12-21z Sat time frame. With low clouds sticking around se KS most of the night, lows may not fall off as much as previously expected. So raised them a few degrees. && .SHORT TERM...(This Evening through Monday Night) Issued at 340 PM CST Fri Dec 9 2016 This Weekend: The thermostat will get turned up considerably for as the inverted surface ridge continues to be pushed east forming a secondary high pressure center over the Ohio Valley, the Front Range surface cyclone will strengthen further to produce stronger southerly flow across central third of the CONUS. The afore-mentioned surface cyclone is still scheduled to move east into KS and Western OK on Sunday. Such behavior would produce a sharp moisture axis that`ll be aligned from TX, thru Eastern OK, to along the KS/MO state line. A relatively weak mid-level shortwave moving quite rapidly east across the Northern and Central Plains will then push a cold front SE that should extend from near the Mid-Mississippi Valley to the Central Red River by Sun Evening. Areas of light rain and drizzle will develop across Eastern KS and most of MO on Sun but will end by Sun Evening as weak surface high pushes SE into KS Sun Night & early Mon Morning. Mon & Mon Night: With a progressive pattern in place the surface high will scoot east, crossing the Mississippi Valley around noon. This allow southerly winds to quickly return to KS to produce one more day of somewhat balmy weather. .LONG TERM...(Tuesday through Friday) Issued at 340 PM CST Fri Dec 9 2016 Highlight: Another blast Arctic air set to invade the neighborhood. Tue-Wed Night: A vicious polar vortex will push eastsoutheast across Central Canada on Tue and intensify further as it crosses Ontario Wed and Wed Night. This would enable another shot of Arctic air to invade the region. We will "chill out" the most Wed and Wed Night with highs struggling to reach the mid 20s and lows from 10 to 15, respectively. Wed may be especially nasty as Northerly 15 to 25 mph winds would certainly put a bite into us. Some post-frontal light snow will spread across KS late Tue Night and Wed but little accumulation should result. Thu-Fri: All will be quiet as strong high pressure dominates. If the ECMWF verifies with a more dynamic pattern, i.e. a MUCH STRONGER Arctic High centered over the Upper Mississippi Valley with a VERY INTENSE cyclone over the Southern Rockies, Southern KS may see a thaw on Fri where a more southerly lower-deck flow would reside. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 533 PM CST Fri Dec 9 2016 Main aviation concern will be the behavior of stratus through most of this taf period. 3,500-6,000ft stratus deck that has lingered across the area most of the day is starting to move out of the western fringes of the forecast area. Should continue to see clearing on the western fringes this evening, clearing out of KICT by 02z. After this evening, confidence in stratus drops significantly. HRRR, RAP and NAM bring another surge of stratus up by late Sat morning, encompassing the entire forecast area by the afternoon hours. With a few models agreeing on this solution, will go with at least a broken deck most of the day Sat but will keep at VFR levels until confidence increases. && .PRELIMINARY POINT TEMPS/POPS... Wichita-KICT 20 45 34 48 / 0 0 0 10 Hutchinson 19 44 32 45 / 0 0 0 10 Newton 20 42 33 44 / 0 0 0 10 ElDorado 21 43 34 48 / 0 0 10 10 Winfield-KWLD 22 45 37 51 / 0 0 10 10 Russell 17 40 27 41 / 0 0 0 10 Great Bend 18 42 28 42 / 0 0 0 10 Salina 17 42 30 42 / 0 0 0 10 McPherson 18 43 31 44 / 0 0 0 10 Coffeyville 23 44 37 54 / 0 0 20 30 Chanute 23 43 34 50 / 0 0 10 30 Iola 22 42 32 49 / 0 0 10 30 Parsons-KPPF 23 43 36 53 / 0 0 10 30 && .ICT WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...RBL SYNOPSIS...EPS SHORT TERM...EPS LONG TERM...EPS AVIATION...RBL
Area Forecast Discussion
National Weather Service Indianapolis IN
958 PM EST Fri Dec 9 2016 .UPDATE... The Near Term section has been updated below. && .SYNOPSIS... Issued at 241 PM EST Fri Dec 9 2016 High pressure over the Missouri Valley will build in across central Indiana tonight and Saturday and result in dry and cold weather. However, that will be short lived as a southern Plains system is expected to bring a variety of winter weather to central Indiana Saturday night through Monday. Two more quick moving systems next week will bring light snow to the area and reinforce the cold air. && .NEAR TERM /Today and Saturday/... Issued at 958 PM EST Fri Dec 9 2016 Aside from minor downward adjustments to min temps per latest LAMP guidance, forecast in excellent shape. Previous discussion follows. Issued at 602 PM EST Fri Dec 9 2016 Will add a flurries mention for the first few hours of the evening. HRRR shows a shallow saturated dendritic growth zone...similar to but much shallower and shorter lived than last night. Remainder of forecast in good shape. Previous discussion follows. Issued at 241 PM EST Fri Dec 9 2016 Models in good agreement that strong high pressure over the Missouri Valley will build in across central Indiana tonight. Model rh time sections, soundings, low level rh progs and satellite trends all favor keeping plenty of stratocu around tonight. In addition, winds will become light. This suggests temperatures will not drop too much tonight, so will go a few degrees above MOS with lows in the upper teens and lower 20s. With high pressure starting off over top of central Indiana, Saturday should be dry. As the high moves off to Appalachia Saturday afternoon, should see the low clouds depart but AC increase as isentropic lift commences. Could see a few breaks in the cloud cover. Plus, low level flow will become southwest. This should allow temperatures to warm back up to the upper 20s and lower 30s or near a MOS blend. && .SHORT TERM /Saturday night through Monday/... Issued at 241 PM EST Fri Dec 9 2016 Main challenge for the short term will be precipitation type, amounts and timing as a low pressure system lifts northeast over the region Sunday night. Models in much agreement that a Rockies system will strengthen over the Texas and Oklahoma panhandles by 12z Sunday and then lift northeast to Lake Huron by 12z Monday. As it does it will drag a cold front across central Indiana overnight Sunday night. This system is expected to bring a variety of winter weather to central Indiana starting Saturday night with far northern sections expecting to see a few inches of snow and the south to see mainly rain. Warm advection will start gearing up Saturday night ahead of the aforementioned system and in the wake of departing high pressure. The GFS was the one model that may be too quick to saturate the column as seen in low condensation pressure deficits Saturday evening. Prefer blend of the other short term models that are slower to moisten things up. At any rate, can not rule out some light snow north of Interstate 70 Saturday night. Small chance pops look good there. By Sunday, isentropic lifts really gets going, and the atmosphere quickly saturates down. 140 plus upper jet will move across southern lower Michigan, enhancing the lift. Precipitation will become widespread Sunday afternoon and night before the precipitation ends Monday morning in the wake of the cold front. Precipitation should start off as snow Saturday night and Sunday morning and gradually transition to a mix of freezing rain, sleet and rain from south to north. By 00z Monday, it should be rain over all but extreme northern parts of the forecast area, where some snow and sleet could mix in. Finally, the precipitation will exit Randolph county Monday morning before ending. Snow totals could reach 3 plus inches in the Kokomo and Delphi areas by Monday morning and quickly drop off to an inch or less from Indianapolis to the south. Total ice accumulation is expected to be less than a tenth of an inch. With models continuing their warming trends, not confident we will see enough snow or ice to warrant a Winter Storm Watch at this point. Watches from adjacent offices are also north of our border counties. && .LONG TERM /Monday night through Friday/... Issued at 214 PM EST Fri Dec 9 2016 The long term pattern looks somewhat active with mostly zonal flow across the area. For Tuesday into Wednesday central Indiana is pinched between building high pressure from the northwest and a surface low moving northeast out of the Gulf. Latest ECMWF and GFS keep an qpf out of the area until Wednesday and removed some pops in the southwest from midday Tuesday through some of the overnight considering that and collaboration. See some potential for a rain snow mix in the south at onset, if any precip occurs Tuesday evening. On Wednesday an upper wave will move through as well, and see some chances for snow with this. Fairly dry as far as moisture is concerned so pops are midrange at best. Temperatures will drop pretty rapidly with northwesterly winds and cold Canadian air spilling down of the back side of the large upper low moving east across Ontario. Wind chills in the single digits Wednesday morning and below zero Wednesday night, Thursday morning and possibly Friday morning. && .AVIATION /Discussion for the 10/00Z TAFs/... Issued at 602 PM EST Fri Dec 9 2016 Mainly VFR through the period, although some brief MVFR ceilings will be possible at times early in the period as ceilings are within a few hundred feet of the borderline. Winds will generally be less than 10kt through the period, remaining northwesterly overnight, and then backing to southeasterly by the end of the period. No significant obstructions to visiblity are expected through the period. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS...MK NEAR TERM...MK/NIELD SHORT TERM...MK LONG TERM...CP AVIATION...NIELD
Area Forecast Discussion
National Weather Service Louisville KY
925 PM EST Fri Dec 9 2016 ...Forecast Update... Issued at 926 PM EST Fri Dec 9 2016 Made a few adjustments to sky cover given recent satellite trends. Also, dropped MinT 1 degree north of I-64 and 1-3 degrees south of I- 64 given current T/Td and the fact that the center of the incoming Arctic high will be directly overhead at 12Z. Issued at 548 PM EST Fri Dec 9 2016 Reflectivities, while still weak, have increased quite a bit north of I-64 so have gone ahead and thrown isolated flurries into the forecast for southern Indiana east of Patoka Lake and central Kentucky north of 64. Also increased cloud cover to 100% where it is overcast. .Short Term (Now through Saturday Night)... Issued at 239 PM EST Fri Dec 9 2016 As of mid afternoon, high pressure over Arkansas and low pressure over the Great Lakes was continuing northwesterly flow over the lower Ohio Valley. Upstream moisture and cold temperatures aloft in the cyclonic flow resulted in an extensive strato-cu deck across southern Indiana and north-central Kentucky. A recent RAP sounding showed these clouds remained in the snow growth region around -12C, and regional radar and surface observations confirm light snow flurries across parts of the area. It`s been a cold day with readings in the mid/upper 20s under the clouds while closer to the TN border temperatures have risen to around the freezing mark. The main focus in the short term is cloud trends and temperatures. Latest visible satellite shows the strato-cu deck extending upstream through Illinois and Indiana. Plan on a mostly cloudy to cloudy night for far northern Kentucky and southern Indiana, and this is where there might be a few flurries around through the night as well. Otherwise, lows tonight will fall into the teens to low 20s. The aforementioned high pressure moves nearly overhead during the day tomorrow and should provide the area with more sunshine and slightly warmer, but still below normal, high temperatures. Readings are expected to top out in the low 30s across southern Indiana to mid/upper 30s across central Kentucky. The high quickly moves east and southerly return flow sets up Sunday night. The tighter pressure gradient should keep the boundary layer mixed enough to hold lows in the mid/upper 20s. .Long Term (Sunday through Friday)... Issued at 241 PM EST Fri Dec 9 2016 A few items of interest in the long term with the focus on the storm system for Sunday and Monday, then another surge of Arctic air for mid/late week. Low pressure is forecast to move from the central Plains toward the Upper Midwest Sunday and Sunday night. Overall, the 09.12z models continued the trend of slowing down the frontal passage Sunday. As a result, collaborated with PAH/OHX/IND to reduce chances early Sunday morning, but still bring in higher chances during the afternoon and evening, west to east. This further reduces the threat of a wintry mix locally. Ahead of it, a push of Gulf moisture will bring higher PWATs between 0.75 and 1.0 inches and combined with stronger forcing for ascent, rain showers should break out across the area, especially Sunday evening and night. Rain will taper off and move east of the area Monday morning. Overall, total rainfall amounts between 0.5 and 0.75 inches are forecast. Temps will be warmer for the first part of the week. Highs look to range through the 40s Sunday and 40s/lower 50s Monday. Temps shouldn`t drop off much Sunday night with lows in the mid 30s to lower 40s. Forecast confidence drops off mid-week as the global deterministic and ensemble models aren`t exactly painting the same picture regarding the synoptic pattern. It does look like a stronger upper level trough will dive toward the region mid-week which will bring another round of colder temperatures (perhaps colder than the current cold snap) but whether any shortwave troughs or surface systems interact with this cold air remains in question. Sided with a model consensus with just slight chances of rain/snow mix Tuesday through Wednesday night. This is a compromise between the dry, cold ECMWF solution versus the wetter, still cold, GFS and GEM. Temperatures will trend downward mid-week onward with highs Thursday and Friday potentially staying in the 20s or low 30s, and morning lows in the teens. && .Aviation (00Z TAF Update)... Issued at 626 PM EST Fri Dec 9 2016 Relatively quiet weather, but still not an easy forecast as we deal with a stubborn stratocu deck over SDF and LEX. Looking at satellite and model data, will give a best stab at when those airports will lose their ceilings this evening. Base heights will be right around 3,000 feet, so the airports will be either VFR or MVFR by just a couple hundred feet at any given time. Interestingly, the RAP, which did an admirable job forecasting this stratus at this time yesterday, shows possible rebuilding of the low clouds late tonight. Again, these would be right around the VFR/MVFR boundary. Will go ahead and include a TEMPO for possible ceilings during the pre-dawn hours, but this will need to be re-evaluated as the evening progresses to see if the signal remains. A weak upper wave crossing the Wabash Valley at this writing is helping to spark a few flurries from the clouds, but those will be of no consequence to aviation. Saturday looks nice with just some mid/high clouds and very light winds as high pressure moves right through Kentucky. && .LMK Watches/Warnings/Advisories... KY...NONE. IN...NONE. && $$ Update.........13 Short Term.....ZT Long Term......ZT Aviation.......13
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Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
752 PM EST Fri Dec 9 2016 .UPDATE... 01Z water vapor and H4 RAP analysis continue to show an unamplified upper level pattern over the CONUS this evening. Northern stream flow runs in a mostly zonal configuration across the mid-section of the country...while the subtropical jet cuts across the Gulf of Mexico and over the southeastern States/FL peninsula before exiting into the Atlantic. High level clouds over our heads this evening are being forced by RRQ dynamics/lift within the exit region of the the subtropical jet core. As this core/jetstreak moves away later tonight/Saturday should the upper level moisture/lift for the clouds. Other than perhaps are far southern zones down toward Fort Myers...this should allow for quite a bit of sunshine to develop Saturday morning. This will be nice...since it will be rather chilly to start the day. Later in the day...winds shift more to the east in the lower levels will begin to deliver some added moisture below 850mb...and this will lead to a sct-bkn fair weather cumulus/stratocu fields in the afternoon. Most fair weather cu will be south of the I-4 corridor where the influx of Atlantic moisture will be greatest. Otherwise...the forecast is dry for the remainder of tonight and Saturday for all zones. Low temperatures by dawn range from the lower 30s over inland Levy county to the middle 40s along the I-4 corridor...and then lower 50s down toward Fort Myers. While a few locations in Levy county may approach freezing for an hour or is unlikely any spots will fall below 32. Also...a steady 4-6mph wind from the north should generally prevent the formation of frost for all but the most sheltered locations. Anywhere from Crystal River south should have no frost/freeze concerns tonight. After the cool start to the morning...temperatures should rebound nicely by the afternoon Saturday. Will see temps into the lower/mid 60s over Levy the upper 60s/lower 70s along I-4...and lower to middle 70s headed southward to Fort Myers. A steady warming trend continues in both overnight lows and daytime highs during the second half of the weekend and early portion of next week. Have a great Friday night and a safe/fun weekend everyone! Stay warm tonight! && .AVIATION (10/00Z through 11/00Z)... VFR conditions will prevail at all terminals through the TAF period. High level clouds will be thinning out and retreating later tonight into Saturday morning...followed by a sct-bkn cumulus field developing during Saturday afternoon. Moderate winds from the northeast through the period. && .MARINE... Elevated winds and seas over the eastern Gulf waters have led to a small craft advisory into Saturday morning. Winds and seas will subside below advisory levels during Saturday and through the remainder of the weekend as high pressure shifts east of the region into the Atlantic. However...periods of near cautionary level easterly winds will remain in the forecast through much of the weekend. && .Prev Discussion... /issued 228 PM EST Fri Dec 9 2016/ SHORT TERM (Tonight through Saturday)... High pressure to continue to build into area with overnight lows near normal in Fort Myers and 5 to 10 degrees colder than normal elsewhere. Temperatures around Williston in Levy County could reach 32 degrees by morning but it is not expected to be widespread. Wind chills in this area could reach 29 degrees but this is still above the wind chill criteria of 25 degrees. The moisture returns quickly this weekend with dew point temperatures warming into the 50s Saturday and 58 to 65 Sunday. High temperatures Saturday to be only 1 to 2 degrees below normal. LONG TERM (Saturday Night through Friday)... Fast zonal flow will over spread the CONUS to kick off the medium range period, setting up a highly progressive weather pattern for several days into next week. Surface high pressure will reside over the eastern half of the CONUS with strong surface cyclogenesis over the Central and Southern Plains regions. This will favor moist southeasterly flow across the Gulf Coast for the first half of the period. From Saturday Night through early next week, we will experience a rather fast warmup as moisture-rich southerly flow persists across the region. Highs will reach the mid to upper 70s and 80s each day with lows only falling into the lower 60s most areas. A weak front will approach the region Monday, but looks to stall to the north as much of the upper level energy driving it southward departs to the north. These scenarios often favor fog and low clouds, and especially marine fog, assuming the shelf waters have cooled substantially. Thus, have opted to add a mention of patchy marine fog beginning Monday night and continuing through at least Tuesday night. Much uncertainty exists as we head into the middle of next week. Several shortwave impulses look to move through the fast zonal flow pattern, producing a highly unpredictable setup. At this time, it does appear a stronger front will near the Florida peninsula during the latter half of next week, but longer range solutions differ wildly on the strength of the front, any associated rainfall, and the depth and intensity of trailing cold air. For now, will lean toward a slow frontal progression late Wednesday into Thursday with only slightly cooler air moving in. However, the ultimate result will likely be vastly different from the existing forecast. FIRE WEATHER... No fire weather and no fog concerns in the forecast through the weekend. && .Preliminary Point Temps/PoPs... TPA 48 71 58 78 / 0 0 0 10 FMY 54 74 61 81 / 10 0 10 20 GIF 48 70 56 78 / 0 0 0 10 SRQ 51 72 59 80 / 0 0 0 10 BKV 42 69 52 78 / 0 0 0 10 SPG 51 70 60 76 / 0 0 0 10 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...None. Gulf waters...Small Craft Advisory until 7 AM EST Saturday for Coastal waters from Bonita Beach to Englewood FL out 20 NM-Coastal waters from Englewood to Tarpon Springs FL out 20 NM-Coastal waters from Tarpon Springs to Suwannee River FL out 20 NM-Waters from Tarpon Springs to Suwannee River FL out 20 to 60 NM. Small Craft Advisory until 1 PM EST Saturday for Waters from Bonita Beach to Englewood FL out 20 to 60 NM- Waters from Englewood to Tarpon Springs FL out 20 to 60 NM. && $$ UPDATE/AVIATION/MROCZKA Previous Discussion...Noah/Austin