Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 09/26/19

Area Forecast Discussion
National Weather Service Columbia SC
1000 PM EDT Wed Sep 25 2019 .SYNOPSIS... High pressure will dominate through tonight. A weak front will move into the area and dissipate late Thursday into Friday. General high pressure and above normal temperatures are expected over the weekend into next week. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... Surface high pressure just offshore will shift farther east tonight. Flat upper ridging will continue. Dry weather anticipated. There will be some increase in low-level moisture in the southerly flow tonight. This moisture combined with nocturnal cooling may lead to areas of stratus and fog late. Expect lows around 70. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/... Thursday/Thursday night... Upper ridge centered over the Gulf of Mexico. Mainly zonal to northwest flow aloft with a few short wave troughs moving through the area. A weak cold front will move into the area Thursday night and become diffuse across the area. Moisture is limited ahead of the front and mid-level ridge/warm temperatures/downslope should limit convection. Have continued a slight chance of showers or thunderstorms mainly north Midlands late in the day and evening. Temperatures will continue above normal with highs in the low to mid 90s and lows around 70. Near record heat possible. Friday/Friday night... Models indicate an increase in moisture with precipitable water increasing to near 2 inches Friday morning along with increasing instability. Frontal boundary/trough lingers in the area. With weak surface convergence and possible moderate instability...scattered thunderstorms may develop by afternoon. However, mid level ridging may limit development. Went with scattered showers and thunderstorms mainly in the afternoon and evening. Temperatures remain well above normal with highs in the low to mid 90s and lows around 70. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... Dry weather and above normal temperatures are forecast for the extended forecast. Strong upper ridging will build back over the Southeastern States through the weekend and linger into the middle of next week. Subsidence associated with the building upper ridge will likely suppress convection. Temperatures will be well above normal through the period. Highs in the low to mid 90s and lows in the 60s to low 70s. && .AVIATION /02Z THURSDAY THROUGH MONDAY/... A sea-breeze boundary moving through the Midlands tonight will provide increased moisture. This moisture combined with nocturnal cooling should lead to areas of fog and stratus early Thursday morning. The HRRR suggests that fog will be favored in the CSRA and western Midlands along the edge of the boundary where moisture is most shallow. Elsewhere, low stratus may be favored for a few hours around and before sunrise. Confidence in IFR or lower restrictions is highest at AGS. At the other TAF sites confidence is not as high and we have continued to forecast periodic MVFR visibilities, but IFR visibilities and ceilings will be possible. Thursday, winds will be light and generally out of the SW, though could become variable at times. The airmass will remain relatively dry and will not support widespread showers and thunderstorms. The chance of thunderstorm-related impacts to the TAF sites remains low. EXTENDED AVIATION OUTLOOK...Restrictions possible in early morning fog and stratus through the extended. && .CAE WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. && $$
Area Forecast Discussion
National Weather Service Huntsville AL
748 PM CDT Wed Sep 25 2019 .NEAR TERM...(Tonight) Issued at 748 PM CDT Wed Sep 25 2019 One thunderstorm remains in southern Cullman County along the southern portion of the larger scale gust front that has pushed through nearly all of northeast AL. A mid level deck of clouds has followed behind, but the chance of further precipitation is declining with loss of daytime heating. The MCS in northeast AR into western TN continues to slowly migrate southeast. The anvil precip with embedded lightning is not making much progress eastward past western TN. The HRRR and other short term models suggest his rainfall will continue to diminish and/or dissipate through the night. So have removed the PoP for later tonight as well. .SHORT TERM...(Thursday through Friday) Issued at 235 PM CDT Wed Sep 25 2019 Dwindling rain chances will be the story for Thursday before the heat really sets back in and builds through the weekend. Temperatures Thursday will top out in the lower 90s, which will make for the `coolest` day of the forecast period/week ahead. Temps will climb a couple of degrees for Friday, topping out in the lower/middle 90s. Sunshine will abound as high pressure aloft builds into the area from the Nrn GOMEX. .LONG TERM...(Friday night through Tuesday) Issued at 235 PM CDT Wed Sep 25 2019 The story of hot and dry will be a broken record for much of the extended, with the upper ridge dominating the weather pattern for the area for the weekend and much of the week ahead. No rainfall is expected for the next 7 days. Temperatures will hover in the middle 90s each day, and I honestly wouldn`t be surprised to see actual temps verify a few degrees above guidance given this pattern aloft and just how dry it is at the surface. Looking ahead at 8-14 day guidance isn`t helping much either, with temperatures indicated to be well above normal and precipitation favoring well below normal. A gander out much further at the 3-4 week guidance from WPC shows much of the same: hot and dry. That said, the farther out in the extended you look, the less mesoscale details matter. We`re holding out hope that the pattern shifts and we finally get a real taste of Fall (and temperatures NOT in the 90s). Hang in there, TN Valley! Fall will get here...eventually. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 617 PM CDT Wed Sep 25 2019 Showers and thunderstorms now SE of a KBGF-KHSV line will likely diminish over the next 1-2 hours. KHSV and KMSL should remain VFR with ceilings at or above 080agl through most of tonight. Although an isolated shower or thunderstorm remain possible through Thursday, will leave out of the terminal forecasts due to low probability and confidence. && .HUN WATCHES/WARNINGS/ADVISORIES... AL...NONE. TN...NONE. && $$ NEAR TERM...17 SHORT TERM...12 LONG TERM...12 AVIATION...17 For more information please visit our website at
Area Forecast Discussion
National Weather Service Wichita KS
853 PM CDT Wed Sep 25 2019 .UPDATE... Issued at 853 PM CDT Wed Sep 25 2019 Latest satellite and 88d radar images show showers and thunderstorms beginning to develop rapidly over south central KS late this evening. This convection is in response to the nose of the 850-925h moisture transport pushing into south central KS. Latest RAP also shows a moderately most unstable airmass, where this convection is developing with 2500-3000 j/kg of MUCAPE. With 20-25 kts of effective shear, could see some strong to severe storms develop along this line of storms. Think hail up to half dollar size and wind gusts to 60 mph are the main concerns. Think convection will continue to develop across southern KS throughout the overnight hours, mainly south of a Kingman to Wichita to Eureka line, as low level moisture transport and isentropic lift continues to focus across southern KS. The low level moisture transport slowly shifts to the east as the overnight progresses, but this will be gradual shift, which may lead to slow movement of the storms and possible training of the convection. So localized flooding will also be a concern into early Thu morning. Ketcham && .SHORT TERM...(This evening through Saturday night) Issued at 339 PM CDT Wed Sep 25 2019 A nearly stalled and rather diffuse surface cold front is draped across southern KS this afternoon. This front may be a focus for surface based convection later this afternoon, however most models suggest much of south central and southeast Kansas will remain capped through late afternoon and early evening. An outflow boundary south of the KS border looks more favorable for afternoon convection with a better axis of instability. Should an isolated storm initiate this afternoon, strong winds and nickel to quarter sized hail will be possible. Tonight a combination of an upper PV wave, a ripple in the 700mb flow, increased moisture transport, along with 310K isentropic lift will induce isolated to scattered elevated storms late evening and overnight. 2,000+ J/kg of 850-300mb MUCAPE and 25-30kts of 1-6km bulk shear would support a few severe storms capable of 1.25 inch hail and gusty winds up to 60 mph. With precipitable water values well above normal, 1.8-2 inches, any storms that do develop will be efficient rain makers. Very heavy rainfall and localized flooding will be possible tonight. Any showers and storms should diminish/move out by mid-morning. Tomorrow should remain fairly quiet as the front retreats northward with highs in the mid 70s. A shortwave will track along the Canadian border tomorrow and push a strengthening sfc low northeast of the Upper Mississippi Valley on Friday. A cold front extending from this low will drag across the Central Plains on Friday. A decent CAPE/shear signal remains in the forecast suggesting severe storms to develop along the front on Friday. The front will continue to meander across the area Saturday which will bring continued chances of showers and storms throughout the day. Expect below normal temperatures across central KS on Saturday with highs near 70 and near normal temps in the upper 70s across south central and southeast KS. .LONG TERM...(Sunday through Wednesday) Issued at 339 PM CDT Wed Sep 25 2019 A warm up can be expected Sunday and Monday with highs in the mid to upper 80s. A southwesterly flow pattern will get locked into place next week as the Central Plains gets sandwiched between a building upper ridge over the Ohio and Tennessee Vally`s and an anomalous trough that deepens over the Great Basin. Another front is expected to pass through the Central Plains Tuesday and Wednesday which will bring increased chances of very heavy rainfall and flooding potential mid week. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 624 PM CDT Wed Sep 25 2019 VFR conditions are expected for the first 12-18 hours or so, with the main concern being a chance of TSRA returning to portions of southern KS late this evening thru early Thu morning. Latest hi-rez model solutions suggest low to mid level moisture transport will increase across northern OK this evening, with most of the moisture pushing into southern KS late this evening. As this moisture and lift increases late this evening, think scattered TSRA will develop along or just north of the KS/OK border and possibly as far north as highway 54 from KICT to KCNU. So plan on going with a VCTS for this chance for the KICT and KCNU tafs from 04-05z to 12z/Thu. Think this will be the only Tafs affected, so will go with VFR conditions elsewhere overnight into Thu. Ketcham && .PRELIMINARY POINT TEMPS/POPS... Wichita-KICT 63 77 71 87 / 30 20 10 40 Hutchinson 59 77 70 85 / 10 10 10 30 Newton 58 77 70 85 / 20 10 10 40 ElDorado 59 77 71 85 / 30 20 10 50 Winfield-KWLD 63 78 71 86 / 60 20 10 30 Russell 54 75 65 79 / 10 0 10 10 Great Bend 56 74 66 80 / 10 0 0 10 Salina 57 78 70 83 / 10 10 10 20 McPherson 57 77 69 83 / 10 10 10 30 Coffeyville 64 79 71 86 / 60 30 10 20 Chanute 61 76 71 85 / 30 20 10 40 Iola 60 76 71 86 / 30 20 10 50 Parsons-KPPF 62 78 71 85 / 50 20 10 30 && .ICT WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...Ketcham SHORT TERM...KMB LONG TERM...KMB AVIATION...Ketcham
Area Forecast Discussion...UPDATED
National Weather Service Twin Cities/Chanhassen MN
1101 PM CDT Wed Sep 25 2019 .SHORT TERM...(This evening through Thursday night) Issued at 245 PM CDT Wed Sep 25 2019 Short term concerns remain isolated showers/thunder over the northeast cwa this evening and convective threat again later Thursday night. Cooler air on breezy west/northwest winds moving across the area this afternoon. Expect winds to diminish this evening. Along with the wind, the threat of mainly light showers will continue across the northeast CWA through about sunset. HRRR continues to indicate a few showers this region this evening. Outside chance of thunder as well, with cool temperatures aloft as trough departs. Jet mid/high level clouds should translate southeast this evening with the cumulus gradually dissipating as well. SHould become mainly clear late with lighter winds and very cool temperatures by Thursday morning. Expecting morning lows mainly in the 40 to 45 degree range, a bit warmer in the larger city cores. Large surface ridge exits to the east during the day Thursday. This will allow southerly flow and an increasing pressure gradient to develop ahead of the Dakotas frontal boundary. We expect mid/high levels clouds to increase during the day with outside chance of some ACCAS showers to develop over the far northwest CWA in the afternoon. Southerly surface winds will also increase with breezy conditions developing west Thursday afternoon, then spreading east into Thursday night ahead of the front. Better shot of showers and thunderstorms developing into Thursday night as the front approaches/heights fall and WAA continues. Best shot will be found over the eastern half of the area later in the night. .LONG TERM...(Friday through Wednesday) Issued at 245 PM CDT Wed Sep 25 2019 The long term period features a classic change of season setup, with a roller coaster ride of warm vs cool sides of multiple active systems passing through the region. By Friday morning, a positively tilted shortwave trough will be centered near the northwest corner of Minnesota, but will lift ENE into Ontario during the day. Associated lift along a trailing front and favorable jet dynamics will produce showers across eastern MN and wester WI mainly in the morning, with dry northwesterly flow filling in behind the front later in the day. High pressure will fill in behind this system into Saturday, which should be an a decent day with highs being held near 60. Attention turns to a developing system across the western CONUS on Saturday, that will intensify and bring strong warm air advection into the region Sunday and southerly flow increases ahead of the system. Showers and thunderstorms are possible Sunday morning, but with the front lifting quickly to our north, drying by the afternoon appears likely. Monday will be a warm day across the area and it wouldn`t be a shock to see 80 degrees on the final day of September. The system that developed to our west over the weekend looks to pass through the local area by Tuesday, then leave the main baroclinic zone nearby or just south of the local area. The main upper trough that will have been parked across the western CONUS will kick out middle of next week, and likely impact the upper midwest by Wed or Thursday with more chances for additional rain. && .AVIATION...(For the 06Z TAFS through 06Z Thursday night) Issued at 1101 PM CDT Wed Sep 25 2019 VFR conditions through Thursday, but some MVFR cigs are remotely possible Thursday night. Winds will back southwest and become gusty Thursday afternoon and evening from west to east with increasing high and mid clouds. KMSP...Will need to watch winds tomorrow evening, they could be stronger than currently forecast. Otherwise, no concerns. /OUTLOOK FOR KMSP/ Fri...VFR. Chance AM MVFR/TSRA. Wind NW 10G20 kts. Sat...VFR. Wind E 5 kts. && .MPX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. && $$ SHORT TERM...DWE LONG TERM...SPD AVIATION...BORGHOFF
Area Forecast Discussion
National Weather Service Marquette MI
628 PM EDT Wed Sep 25 2019 .SHORT TERM...(This evening through Thursday) Issued at 427 PM EDT WED SEP 25 2019 Water vapor imagery and RAP analysis show a trof extending from central Canada into the n central CONUS. Upper MI is falling under the broad, deep cyclonic flow of the trof with axis of 130kt upper jet extending from SD to s central and eastern Upper MI. The cyclonic flow and modest caa at 850mb has led to an increasing cu cloud field this aftn along with isold -shra. Shra are becoming more nmrs across ne MN toward western Upper MI underneath cyclonic side of upper jet and in advance of a weak shortwave. Expect a continued increase in shra coverage over the next few hrs as approaching weak shortwave and daytime instability support shra development. Could be a few rumbles of thunder with a couple hundred j/kg of MLCAPE per SPC mesoanalysis. Upper MI becomes positioned more solidly on the cyclonic side of the upper jet tonight with mid- level trof axis arriving. So, it may take more time than usual for shra to dissipate after the loss of solar insolation. In addition, cyclonic flow and 850mb temps falling to around 2C overnight over sfc water temp of 13-14C may be sufficient for a little lake enhanced -shra activity, mainly into the eastern fcst area. Will be a much cooler night with low temps mostly in the 40s. Any lingering -shra into the ne fcst area will end during Thu morning. Otherwise, expect clearing skies from w to e during the morning into the early aftn though there will probably be an expansion of stratocu for a time in the morning once daytime heating commences and before 850mb thermal trof departs. High clouds may begin to spread into the area from the w in the aftn, resulting from strengthening waa regime upstream ahead of the next shortwave approaching the Northern Plains. High temps will be within a few degrees of normal for late Sept, generally lower 60s. .LONG TERM...(Thursday night through Wednesday) Issued at 308 PM EDT WED SEP 25 2019 Thursday evening, sfc low pressure centered near the ND/Manitoba border with be quickly traversing eastward to the Boundary Waters, but it is expected to take a turn to the northeast through the morning hours of Friday and head toward James Bay by Friday night. Q- vector convergence will be maximized over northwestern Lake Superior overnight, and that`s where the majority of the rain will set up initially, with just scattered showers over the UP mainly after midnight. Strong winds will increase quickly through the early morning hours, and during the day widespread wind gusts of 20-35 mph are expected. Wouldn`t be surprised to see an isolated 40 mph report. And as the cold front approaches and swings winds from the S to the SW and eventually W in the late afternoon, it will also bring some additional shower chances, especially over the east late. The better dynamics will remain north of Upper Michigan during the day, so it`s not looking like an all day rainout but definitely will be dodging raindrops from time to time. A strong warm nose a around 5k ft should preclude any thunder as instability will remain well to our south. A couple showers may linger over the far east into Friday night, but high pressure will be quickly knocking at the doorstep and pushing much drier and cooler air into our region. Saturday night and especially Sunday night lows over the interior will fall well into the 30s, and frost headlines will remain possible these nights. High temperatures will be cooler than average as well over the weekend, only reaching the mid 50s to upper 60s. Late Sunday, the high will be pushed out to the east as a large, closed western CONUS trough digs in and stays put for a few days. This will allow for a much more active pattern early next week over our region. A surface low is expected to develop over Colorado or Wyoming Sunday night and push northeast, with Upper Michigan generally in the warm sector Monday into Tuesday. This will allow for well above normal temps Monday, but also periods of showers and thunderstorms early next week. The potential strong thunderstorms remains for Monday, and heavy rainfall will also be possible through the first half of next week. Shortwave energy will intermittently ride the eastern periphery of the trough northeastward through Wednesday before the pattern finally becomes progressive again, likely pushing the western CONUS trough through the Upper Great Lakes around next Thursday, give or take. For now, many deterministic models keep the heavy rainfall threat next Tuesday night into Wednesday to our south over WI, but will have to keep an eye on trends as the GEFS mean is further to the north. A slight northward shift could mean more rain over southeast Upper MI where they`ve already seen 1.5-4+ inches of rain in the last week, or 150-300+ percent of normal. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 627 PM EDT WED SEP 25 2019 VFR conditions are likely to prevail at KIWD/KCMX/KSAW thru this fcst period. Isold to sct shra will continue into the evening. Since potential of any of the terminals being affected is low, only VCSH was included in fcst. Otherwise, gusty winds are expected thru most of this fcst period at KCMX. Gusts will be around 25kt tonight into Thu morning. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 427 PM EDT WED SEP 25 2019 Under a tight pres gradient and influx of colder air, expect westerly winds of 20-30kt across much of Lake Superior tonight. There may be few gale force gusts to 35kt. Winds will diminish to mostly under 20kt Thu aftn, though gusts to around 25kt will continue for much of the day btwn the Keweenaw and Isle Royale. Winds will then ramp up again late Thu night/Fri as the next cold front approaches and passes. Southerly winds of 20-30kt will develop ahead of the front. High obs platforms over the e half of Lake Superior may see several hours of gale gusts Fri morning. After the front passes, a decent push of colder air and incoming sharp pres rises are suggestive of a period of w to nw gales, especially across central and eastern Lake Superior. Winds will then diminish Sat as high pres ridge builds toward the area. By Sat night, winds will be under 15kt. Winds will be on the increase again Sun into Mon as the ridge shifts e and low pres lifts from the western Plains toward the Upper Lakes. Winds will probably increase to 20-30kt for a time at some point later Sun/Mon. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... Beach Hazards Statement until 9 PM EDT this evening for MIZ006- 014. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...Rolfson LONG TERM...KCW AVIATION...07 MARINE...Rolfson
Area Forecast Discussion
National Weather Service Omaha/Valley NE
946 PM CDT Wed Sep 25 2019 .SHORT TERM...(Tonight through Saturday) Issued at 317 PM CDT Wed Sep 25 2019 Another mild day Thursday followed by rain chances into the weekend are the primary highlights of the forecast. Extensive mid level clouds associated with shortwave swinging through the Dakotas covered the northern half of eastern Nebraska and southwest Iowa this afternoon. Isolated reports of light rain or sprinkles were noted within this cloud shield, and expect this to continue into the evening until short wave and associated 130kt upper jet shift east. RAP and HRRR have been hinting at a stripe of light precip across our area, so will add small PoPs for this occurrence. Surface high pressure will follow later tonight but quickly moves away allowing southerly return flow to set up Thursday morning. Clouds should also move east making for a pleasant Thursday afternoon. However returning moisture late in the day and overnight will provide fuel for potential elevated convection Thursday night as 40-50kt low level jet overspreads the region ahead of approaching cold front. GFS and ECMWF suggest near 1500 J/kg of elevated CAPE will overspread the southern half of our CWA along with 35kt of bulk shear. Will increase thunder chances Thursday night and maintain a chance for rain until front slides southeast Friday afternoon. Mid level trough begins to deepen in the West later Friday night and Saturday, providing southwest mid level flow across the Plains and inducing intensifying southerly low level jet. Moisture advection will be well underway when weak shortwave is ejected into our region Saturday afternoon as per both GFS and ECMWF. Showers may begin Saturday afternoon, but are more likely Saturday night as low level jet really starts to kick in. .LONG TERM...(Saturday night through Wednesday) Issued at 317 PM CDT Wed Sep 25 2019 The longer term period for the rest of the weekend into the middle of next week looks unsettled as southwest mid level flow ahead of Western trough remains over the Plains. Along with from occasional shortwaves ejecting into the region, persistent theta-e advection should keep atmosphere primed for convection. Thus episodic rain chances remain in the forecast. Rain chances increase Saturday evening as low level jet ramps up. Elevated instability is most notable after midnight, but could see at least isolated lightning strikes Saturday evening. Southerly surface flow returns for Sunday when dew points are expected to approach 70 once again. If there is a dry period in the long term period, it would appear Sunday afternoon and night offer the best chance to remain precip-free. A cold front trailing a Northern Plains shortwave will begin to enter the region later Monday into Tuesday, just in time for a potent shortwave to eject across our region. Thunderstorm chance will increase Monday, with front stalling somewhere either in or just south of our CWA as frontal zone becomes parallel to mid level flow. Severe storms are possible given at least modest instability in a high shear environment, but heavy rain appears to be the main threat under high precipitable water regime and likely training of convection. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 944 PM CDT Wed Sep 25 2019 VFR conditions are expected throughout the TAF cycle. A few light showers or sprinkles may move through overnight during the first few hours of the TAF but looks like it will remain very spotty so did not include a mention in the TAF. Surface winds will turn to the south Thursday and gust to near 25kt by afternoon. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...None. IA...None. && $$ SHORT TERM...Dergan LONG TERM...Dergan AVIATION...Kern
Area Forecast Discussion
National Weather Service Nashville TN
834 PM CDT Wed Sep 25 2019 .UPDATE... FOR EVENING DISCUSSION. && .DISCUSSION... After scattered showers and a few thunderstorms pushed across southern Middle TN late this afternoon, things have quieted down. Still looking at a few spotty showers south of I-40, and potentially a few more moving in from West TN, but latest guidance would suggest these will be dissipate over the next couple of hours, likely before they reach I-65. Still seeing a fairly drastic warm front draped across the region this evening, with low to mid 50s dew points in East KY and TN and low 70s dew points over our south, back into West TN. Models continue to push a cold front through the region tomorrow morning and this cold front should be the instigator for additional showers and a few thunderstorms through the day tomorrow. QPFs look good -- much needed rain -- but nothing out of hand and storms should be fairly well behaved as cloud cover keeps temperatures down. By this time tomorrow, the cold front and associated activity should be south of the state and slightly lower dew points should advect in behind it allowing for cooler morning temperatures come Friday. While we`re likely to catch a break from the heat tomorrow due to the showers and cloud cover, by Friday afternoon, we should be right back into the low 90s with a stretch that could last into October. Fall? Where are you, Fall? && .AVIATION... 00Z TAF DISCUSSION. BNA/MQY/CKV/CSV...Another surface boundary sits to our north this evening with scattered showers passing across Middle Tennessee, primarily south of I-40. The HRRR shows very little additional activity developing through the overnight period, with convection regenerating tomorrow with the passage of the actual front. At this time, POP`s are too low to warrant mention in the TAF`s, with the exception of CSV, where showers are most likely to occur during the afternoon. Outside of showers, look for VFR wx the next 24 hrs. && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ DISCUSSION......Unger AVIATION........08
Area Forecast Discussion
National Weather Service Blacksburg VA
848 PM EDT Wed Sep 25 2019 .SYNOPSIS... A cold front from the Great Lakes to the Central Plains will move east tonight and Thursday before stalling over the Carolinas on Friday. Another front will move through the Ohio Valley on Saturday then stall over the Tennessee Valley and Mid Atlantic region on Sunday then wedging down the Appalachians Monday. && .NEAR TERM /THROUGH THURSDAY/... As of 848 PM EDT Wednesday... A cold front to our west will move southeast tonight into Thursday. Mid and high clouds are spreading east into our region ahead of the front tonight. Made some more adjustments to temperatures for tonight using the latest NBM. The HIRES-ARW- East and HRRR bring some isolated convection into our area after 12z Thursday. However, any showers will be fighting the drier air across our region. Isolated to scattered showers and thunderstorms are possible Thursday afternoon. The best chance will be in the west. As of 725 PM EDT Wednesday... Made some minor adjustments in temperatures utilizing the latest surface obs, their trends and shape towards NBM for this evening into tonight. More changes later tonight. As of 1255 PM EDT Wednesday... Long wave trough crosses through the northern stream tonight and Thursday which will push a surface cold front through the Mid Atlantic region Thursday. Winds will be southwest to west ahead of the front tonight then become northwest behind the front on Thursday. Precipitable water values increase to around 1.5 inches but with the westerly component of the wind, the probability of rain will be higher in the mountains than in the foothills and piedmont. Mid and high clouds increase from the west this evening with the cloud bases lowering throughout the night. The chance of precipitation begins on the western slopes of the central Appalachians after 06Z/2AM with the best chance across much of southwest Virginia, northwest North Carolina and southeast West Virginia after 12Z/8AM. Lifted index in the 0 to -4 range with surface dew points back into the 60s leading to Convective Available Potential Energy of 500-1000 J/kg during the afternoon so will add isolated thunder in the forecast Thursday. Cloud cover tonight and rising dew points will limit drop in temperature. Will be leaning toward NBM numbers. Starting mild in the morning so will stay on the warm side of guidance for afternoon highs. This means maximum temperatures will be 5 to 15 degrees above normal. && .SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/... As of 345 PM EDT Wednesday... High pressure will drift over the Mid Atlantic by Thursday night and maintain control into Friday. This area of high pressure should move offshore during Friday night. Meanwhile, heights will rise aloft to build an anomalously strong upper level ridge over the Southeast by the start of this weekend. Confidence remains high that Friday should stay dry. High temperatures on Friday were kept a few degrees cooler than Thursday in the wake of the weak cold front exiting off the North Carolina coast. By Saturday, the increasing heat and humidity may provide enough instability to spark isolated afternoon showers and thunderstorms in the mountains. The latest ECMWF has increased the coverage of convection slightly compared to previous runs, which puts it in better agreement with the GFS. Given the persistent dry trend from this month, cautious optimism was utilized by only raising the POPs a little for midday Saturday into early Saturday night. Temperatures were maintained in close agreement with the ECMWF MOS and the NBM, which have been performing much better than any other model guidance during this unseasonably warm period for late September. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... As of 345 PM EDT Wednesday... The unseasonable warmth will continue into Sunday due to an impressive upper level ridge over the Southeast. A cold front will dive southward over the Northeast thanks to high pressure over eastern Canada pushing the frontal boundary in the same direction. The combined influence of heat and humidity with this approaching frontal boundary should spark another chance of afternoon showers and thunderstorms across the mountains. Again, POPs were only increased slightly for Sunday afternoon to account for the prevailing dry trend. As this area of high pressure builds southward and wedges against the eastern slopes of the Appalachian Mountains during Sunday night into Monday, the frontal boundary will become a backdoor cold front and head southwestward over Virginia. The resulting easterly flow should advect Atlantic moisture along this frontal boundary to provide a chance of light showers, especially along the Blue Ridge where upsloping would occur. Consequently, high temperatures on Monday were pushed toward the cooler side of guidance. Once the backdoor cold front clears the CWA by Tuesday, surface high pressure should take hold over the Mid Atlantic to bring warmer and drier weather through Wednesday. && .AVIATION /01Z THURSDAY THROUGH MONDAY/... As of 735 PM EDT Wednesday... VFR conditions will continue this evening into tonight. A cold front will approach the area tonight then cross into North Carolina on Thursday. Mid and high clouds will increase from the west ahead of the front this evening and overnight. If high clouds take long enough to reach the Virginia and North Carolina piedmont there may be some MVFR fog. Kept a couple hours of fog in KDAN late tonight into THursday morning. Scattered showers are expected in the mountains, mainly in the morning. Isolated showers are expected east of the Blue Ridge and isolated thunderstorms are possible in the afternoon. The probability was too low to include in the KROA, KLYH or KDAN TAFs at this time. Behind the front Thursday afternoon,ceilings drop to MVFR. KLWB and KBLF have best chance for MVFR ceilings. Medium to high confidence in ceilings, visibilities and winds during the taf period. .Extended Aviation Discussion... MVFR or lower upslope clouds will remain across the western flanks of the Appalachians Thursday night. VFR conditions are expected east of the Blue Ridge. Dry weather is expected on Friday. Isolated MVFR shower or thunderstorm is possible on Saturday and Sunday along the Blue Ridge. An isolated MVFR shower is possible on Monday. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...AMS NEAR TERM...AMS SHORT TERM...PW LONG TERM...PW AVIATION...AMS/KK
Area Forecast Discussion
National Weather Service San Diego CA
200 PM PDT Wed Sep 25 2019 .SYNOPSIS... A stalled low pressure system over northern Baja California will bring a chance of showers and thunderstorms late this afternoon through Thursday with the best chances of measurable rain over the mountains and deserts. There will be a cooling trend through Thursday. A trough will deepen over the west coast this weekend bringing cooler weather, a deeper marine layer, and a chance of light showers west of the mountains Saturday. The cool weather will continue through early next week with some warming by the middle of next week. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... Partly cloudy skies prevailed at early afternoon. Temperatures are mostly a little lower versus 24 hours ago, with greatest temperature falls in the valleys, where some locations are 10 degrees lower than 24 hours ago. HRRR and local WRF runs plus SREF/GEFS ensembles show precip, mostly in the form of banded convection moving around the low starting very late this afternoon or even early this evening. A lot of the precip will be driven by instability aloft versus at the surface and generally will be fast moving due to mid-level winds averaging around 30 knots, so precip amounts generally will not be great, mostly 1/4 inch or less, though isolated thunderstorms in the deserts/desert mountain slopes could produce locally more. Some of the precip could drift west of the mountains. Some lightning was detected over the mountains of Northern Baja about 100 miles south of the US/Mexico border and some in far SW AZ/NW Sonora, but a few lightning strikes are possible in the banded convection over our forecast area when it arrives. Local gusty winds will be possible with the storms. Model guidance suggests precip chances decrease some Thursday and should be gone entirely by Thursday evening. Upper low will dominate the West Coast this weekend with all ensemble models in agreement with occurrence but some disagreement in timing of the trough axis passage. The marine layer will become quite deep, probably 5000 feet or more, and with the surface eddy- like flow, that could be enough to bring a few showers from the coastal mountain slopes west to the coast. Most rainfall amounts should be light, under 1/4 inch. Temperatures will be overall about 10 deg F below normal. Areas of strong gusty winds will be likely in the mountains and deserts. The long-wave trough will likely be slow to move east through the Western US early next week, so that will result in cyclonic flow here and temps remaining below normal through about Tuesday with possible warming around Wednesday if the flatter west flow aloft shown in the ensembles verifies. && .AVIATION... 251940Z...Coast/Valleys...A coastal eddy is keeping low clouds with bases around 1400 ft MSL along the northern San Diego County coast. Mod confidence low clouds will scatter out later this afternoon. Otherwise, high clouds AOA 15000 ft MSL across the area. South to southwest winds with gusts 15-25 kt are possible at coastal TAF sites through Thu AM. -SHRA and isolated TSRA possible this evening and overnight. Patchy areas of low clouds with bases 800-1200 FT MSL will start to develop around 06Z Thu. VIS 2-4 SM possible in areas of -SHRA and where low clouds near higher terrain. Low clouds and vis restrictions will clear by 17Z Thu. Mountains/Deserts...-SHRA and isolated TSRA possible this evening and overnight. Reduced VIS from rain is expected with storms, along with strong up/downdrafts, gusty surface winds and lightning. && .MARINE... Isolated showers are possible Thursday morning. Otherwise, no hazardous marine weather is expected through Monday. && .SKYWARN... Skywarn activation is not requested. However weather spotters are encouraged to report significant weather conditions. && .SGX WATCHES/WARNINGS/ADVISORIES... CA...NONE. PZ...NONE. && $$ PUBLIC...Maxwell AVIATION/MARINE...CO
Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
802 PM EDT Wed Sep 25 2019 .UPDATE... The latest RUC model shows deep layer ridging centered in the east half of the Gulf of Mexico for tonight with a northeasterly to easterly 1000-700 MB flow. The surface gradient is relaxed which allowed a sea breeze to form along some coastal locations earlier this afternoon...otherwise light and variable winds overnight. Model PWAT values along with the ascending TBW sounding both indicate a fairly dry air mass in place although there could be a few clouds around. Temperatures currently in the mid to lower 80s are on track to drop into the lower 70s to upper 60s. && .AVIATION... 26/00Z Issuance. VFR and WX free conditions. Winds become light and VRBL overnight then pick up AFT 15Z but no more than 07KT with an onshore component...except PGD/FMY/RSW become ENE. && .MARINE... Relaxed high pressure will keep winds light to gentle and allow afternoon sea breezes for the next couple of days. This high pressure gets reinforced over the weekend and along with tropical cyclone Karen east of the Bahamas will result in increasing winds and seas...near or at caution to advisory levels. && .Preliminary Point Temps/PoPs... TPA 73 91 73 91 / 0 0 0 0 FMY 71 90 71 90 / 0 0 0 10 GIF 71 93 71 92 / 0 10 0 0 SRQ 72 90 73 90 / 0 0 0 0 BKV 70 92 70 92 / 0 10 0 10 SPG 74 90 74 91 / 0 0 0 0 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...None. Gulf waters...None. && $$ Rude/Jillson/Flannery/Norman
Area Forecast Discussion
National Weather Service Tucson AZ
240 PM MST Wed Sep 25 2019 .SYNOPSIS...An active weather pattern will continue through Thursday as an upper level low west of the area produces showers and thunderstorms across the area. Locally heavy rainfall and strong thunderstorm outflows will be possible. Less activity expected Friday then dry conditions this weekend into early next week. && .DISCUSSION...The meteorological saying "A cut-off upper level low is weatherman`s woe" is very appropriate for today. The upper level low that was over northern Gulf of California earlier this morning has drifted WNW into northern Baja, and further west than what recent model runs have been depicting. Thus conditions today have not developed as planned 24 hours ago. Latest HRRR showing some strong thunderstorms developing over the next 3-5 hours from Tucson west. SPC has this area under marginal risk for severe storms into this evening. With respects to the current flash flood watch that is in effect until 5 am Thursday, the lack of activity today across eastern Pima/Santa Cruz/ern Pinal/western Graham and Cochise counties I have decided to cancel the flash flood watch for these areas. The better threat will remain W/NW of Tucson. The northern Baja cut-off low will lift N into far SE CA/SW AZ by Thursday morning and then open up Thursday evening as it lifts NE across the state into Friday. Chance of showers and thunderstorms for Thursday then a slight chance on Friday NE of Tucson. Dry weekend into early next week and then we may see a return of some tropical moisture after Wednesday. && .AVIATION...Valid through 27/00Z. Isolated SHRA/TSRA will increase in areal coverage thru the evening hours tonight before diminishing early Thursday. West of KTUS, SCT clouds at 6k-9k ft MSL will becoming BKN-OVC at 4k-8k ft MSL this evening and persist thru Thursday morning. From KTUS east, SCT-BKN clouds at 4k-8k ft MSL and OVC clouds AOA 15k ft MSL. MVFR ceilings and even occasional IFR conditions in and around thunderstorms. SFC wind generally less than 12 kts. Wind gusts to 40+ kts near TSRA and with any thunderstorm outflow boundaries. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...An active weather pattern will continue through Thursday as an upper level low produces showers and thunderstorms across the area. Locally heavy rainfall and strong thunderstorm outflows will be possible. Less activity is expected Friday, then dry conditions are expected this weekend into early next week. 20- foot winds will be terrain driven and less than 15 mph, except in the vicinity of thunderstorms where strong, gusty and erratic winds will be possible. && .TWC WATCHES/WARNINGS/ADVISORIES... Flash Flood Watch through late tonight for AZZ501>507-511-513>515. && $$ Visit us on Facebook...Twitter...YouTube...and at