Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 09/28/17

Area Forecast Discussion
National Weather Service Denver/Boulder CO
806 PM MDT Wed Sep 27 2017 .UPDATE... Issued at 805 PM MDT Wed Sep 27 2017 Latest observational data from GOES-16 and local area radars are showing the leading edge of the precipitation shield moving across Elbert/Douglas and Arapahoe Counties. This batch of rain will move north and northeast with time, impacting Denver metro around 10 PM or so then north to Fort Collins/Greeley by midnight. Most areas along the Front Range and points east to Kansas should see a nice soaking rain overnight tonight and into Thursday morning. Snow lovers can get excited tonight because the latest HRRR and HRRRX model runs have consistently shown 1-5 inches of accumulating snow overnight as low as 9500 feet, especially across Northern Park County, Mosquito Range, Gore Range, and southern Front Range Mountains including the I-70 corridor from Vail Pass to Silver Plume. Amounts on road surface not likely to amount to much given warm road surface temps and relatively warm air temps. This is associated with the leading shortwave trough rotating out of the main trough currently located over northern Arizona and falls in line with the regional/global model guidance as well. Current forecast package includes these impacts well and thus no changes were needed. && .SHORT TERM...(This evening through Thursday) Issued at 317 PM MDT Wed Sep 27 2017 Upper level low is spinning over northern Arizona this afternoon, and will lift slowly northeast tonight and Thursday. By Thursday afternoon, it should be located in eastern Utah. Cool and unsettled weather will remain in the forecast for this period, with rain showers and higher mountain snow becoming more widespread tonight. Current radar shows scattered showers over the forecast area. Airmass appears to be only marginally unstable, still enough for convective shower development but not enough for thunder even in the mountains. Latest IR imagery shows slight cloud top cooling, but shower coverage still somewhat limited. Later this evening into the overnight, we should see more widespread precipitation coverage develop with persistent but weak Q-G forcing. Southeast flow across the Palmer Divide will cut back QPF from Denver northward, but we should still see showers make it over the Divide with enough support and marginal instability. In the mountains, we did lower the snow levels a bit more based on the cold core of the upper level low nudging toward the forecast area. 700 MB temps drop to near 0C, so snow levels could lower to as low as 9000 feet, with those lower levels in the Park County area. Snow forecast look on track, with 2-6 inches generally expected through tomorrow morning in elevations above 10,000 feet. Should see some slush develop on higher mountain passes, including the approaches to the Eisenhower Tunnel, Berthoud Pass, and Cameron Pass during the heavier snow showers. Showers should continue into Thursday morning with the continued lift in the neutral airmass. Overall, have adjusted PoPs and QPF upward for later tonight through Thursday morning with a slightly later arrival of best lift and jet forcing. Then showers are expected to decrease (at least on the plains) Thursday afternoon. Mountains should continue to see numerous showers into the afternoon with sufficient instability and convective redevelopment. .LONG TERM...(Thursday night through Wednesday) Issued at 317 PM MDT Wed Sep 27 2017 Thursday night into Friday the upper low continues to drift northward into Wyoming with a moderate southwesterly flow aloft over Colorado. The atmosphere on Friday will be drier but somewhat more unstable. The increased instability combined with lingering moisture and weak QG forcing associated with a 60kt upper jet should result in isolated to scattered showers and storms...most numerous over the northern mountains and foothills. Upper air soundings indicate a strong cap across the far eastern plains which may prevent any storms from forming in those areas. Over the weekend...a broad upper level trough will cover the northern Rockies and northern Plains States...with a moderate to strong westerly flow aloft setting up over Colorado. On Saturday...QG lift associated with a 100kt+ jet streak moving over northern Colorado may result in another batch of showers and storms across the northern two thirds of the CWA during the late afternoon and evening hours. A much drier subsident airmass is expected to move into north central and northeastern Colorado Sunday and Monday as the upper jet moves north of the state. This pattern should produce mostly dry weather across all of the north central and northeastern Colorado with breezy to windy conditions over the mountains and foothills. On Tuesday...models show an upper level storm system deepening along the West Coast of the United States as an upper level ridge of high pressure builds over the southeastern U.S. This pattern will put north central and northeast Colorado under a southwesterly flow aloft resulting in mostly dry conditions and above normal temperatures. By Wednesday...some subtropical moisture may work its way north into the state...with a few afternoon and evening showers and storms possible mainly across the high country. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 805 PM MDT Wed Sep 27 2017 A batch of rain showers is approaching the metro area airports this evening. Latest GOES-16 and radar trends has it arriving later than 02Z for APA and 03Z for DEN/BJC but close enough that TAFs were left alone for now, especially given that the rain itself shouldn`t decrease CIG/VIS much at the onset. We expect CIGs and VIS to gradually decrease overnight tonight, bottoming out around 11/12Z. For now feel could be IFR BKN CIGs in the 005 to 008 range by 12Z. VIS in the rain could get as low as 3SM but not as confident in the evolution of the VIS as with CIGs and winds. Winds should be SE at APA and DEN around 10 kts overnight. BJC impacted by weak Denver Cyclone and should remain 5 kts or less out of the NW. Thursday CIGs should improve midday into the MVFR category but BKN to OVC skies will persist through Thursday evening overnight into Friday. Looks like a decent chance of rain showers with low MVFR conditions possible Thursday afternoon. Winds will be 10-12 kts or less again Thursday afternoon and evening, with a general shift to NE then N into the overnight hours. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...Schlatter SHORT TERM...Barjenbruch/Sullivan LONG TERM...Kalina AVIATION...Schlatter
Area Forecast Discussion
National Weather Service Caribou ME
914 PM EDT Wed Sep 27 2017 .SYNOPSIS... A strong cold front will push the northern Maine tonight bringing with it the chance for scattered strong thunderstorms. More seasonable temperatures will return for the remainder of the week with high pressure and dry conditions. && .NEAR TERM /THROUGH THURSDAY/... 9:15 PM Update...Showers and thunderstorms having been moving to the east at around 50 mph across northern Maine to the north of Greenville this evening. The severe threat has ended across far northern areas, but will continue for another hour or so across central portions of the CWA. Low clouds and areas of fog have moved north off the ocean and into much of the Downeast Region late this evening. The low clouds will likely make it about as far north as Topsfield in Washington County before getting nudged back toward the coast toward morning as the cold front presses south. Main updates are to the PoPs and weather for the next few hours based on the latest radar trends. Previous discussion... Storms have begun to develop well ahead of the main cold front that is currently in the Saint Lawrence Valley. HRRR has been consistent holding this line together to the Quebec/Maine border with the possibility of some bowing segments developing. Strong shear profile does support the potential for some isolated severe gusts, but the line is coming in after sunset, with the main question being if any surface stable layers develop. MUCAPE values are expected to remain above 1000 J/KG through 0300z across the north. We will watch how this evolves tonight, but short fused warnings across the north are still a possibility. The line is expected to weaken quickly as it pushes into central Maine, with limited to no rain expected for the Penobscot Valley and most of Downeast. Storms could fire along the coast late tonight, but most of the action is expected to stay off shore. Overall some much needed rain will be received, but only across northern Maine with dry conditions for Bangor region and Downeast. Thursday back to reality as cooler Canadian airmass moves into the area with high temps trending down 20 degrees for some areas compared to today. It will be breezy out of the northwest also making it feel like fall, with partly cloudy skies. && .SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/... Much cooler air continues to filter in from the northwest Thursday night and Friday. Should remain breezy Thursday night, keeping surface temperatures from cooling off too frost/freeze levels. Friday looks quite chilly and breezy, with highs around 50 in far Northern Maine and around 60 Downeast. Could be a some stratocumulus clouds especially over the north, but don`t expect any precipitation. Pressure gradient relaxes some Friday night and although high pressure is still centered well off to the west, think that winds will let up enough to allow frost/freeze conditions in roughly the northern half of the area. Will mention in hazardous weather outlook. A nice, crisp fall day for Saturday. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... Potent upper level low looks to pass to our east Saturday night and Sunday. This shouldn`t have too much of an impact other than to increase winds Saturday night and Sunday. Looks like high pressure could build in Sunday night, setting the stage for another potential frost/freeze. Then turning warmer Monday to Wednesday as high pressure slides off to the east. This airmass will be a far cry from what we have been seeing, but still will be warmer than average with generally mid 60s to mid 70s for highs. Next shot at rain is with a potential cold front around Wednesday or Thursday, although from about Wednesday onward model agreement gets much worse so confidence on any solution is low. && .AVIATION /01Z THURSDAY THROUGH MONDAY/... NEAR TERM: Predominately VFR from KPQI north to KFVE with local MVFR conditions. A period of IFR possible at KHUL late this evening in thunderstorms with gusty and erratic wind. Thunderstorms are not expected at KBGR/KBHB tonight as the cold front swings through the area. IFR and LIFR conditions in low clouds and fog are expected tonight at KBHB and KBGR with improvement to VFR Thu morning by 12-13Z. SHORT TERM: From Thursday night through Friday, generally look VFR with breezy conditions. However, can`t rule out some MVFR ceilings from time to time over Northern Maine from a stratocumulus cloud deck. VFR expected areawide Friday night into early next week. && .MARINE... NEAR TERM: Large long period swells from Maria will continue through Thursday so have left up the small craft advisory. Swells are expected to build and peak late Thursday into Thursday night. Another thing will be the potential for thunderstorms late tonight into Thursday morning, but looks like most of the activity will occur in the outer waters of the Gulf of Maine. Winds will switch to the NW tomorrow and increase through the day as the cold front pushes well offshore and high pressure builds over the waters. SHORT TERM: Still some pretty good combined seas thanks to Maria Thursday night into Friday, then seas gradually ease Friday night through the weekend, down to about 4 feet on Saturday and 2 feet on Sunday. Low seas into early next week. For winds, potential small craft offshore winds Thursday night. Otherwise, generally sub-small craft winds. && .TIDES/COASTAL FLOODING... Currently long period swell from Tropical Storm Maria, which is running at 14-16 seconds/6-7 feet, is entering the Gulf of Maine. The long period swell is expected to persist into Thursday and peak late Thursday afternoon into Thursday night. Since Maria is still located directly south of New England, the higher wave systems are partially blocked by the configuration of the Southern New England Coastline. As the storm moves further out to sea late today the Gulf of Maine will be directly exposed to the higher waves near the center of the storm. This is why we expect things to peak late Thursday afternoon into Thursday night. As a result of the large and long period waves a High Surf Advisory will remain in effect through Thursday night. However, coastal flooding and beach erosion is not expected. && .TIDES/COASTAL FLOODING... Currently long period swell from Tropical Storm Maria, which is running at 14-16 seconds/6-7 feet, is entering the Gulf of Maine. The long period swell is expected to persist into Thursday and peak late Thursday afternoon into Thursday night. Since Maria is still located directly south of New England, the higher wave systems are partially blocked by the configuration of the Southern New England Coastline. As the storm moves further out to sea late today the Gulf of Maine will be directly exposed to the higher waves near the center of the storm. This is why we expect things to peak late Thursday afternoon into Thursday night. As a result of the large and long period waves a High Surf Advisory will remain in effect through Thursday night. However, coastal flooding and beach erosion is not expected. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...High Surf Advisory until 8 AM EDT Friday for MEZ029-030. MARINE...Small Craft Advisory for hazardous seas until 8 AM EDT Friday for ANZ050>052. && $$ Near Term...CB/Dumont Short Term...Foisy Long Term...Foisy Aviation...CB/Dumont/Foisy Marine...CB/Dumont/Foisy Tides/Coastal Flooding...Foisy
Area Forecast Discussion...UPDATED
National Weather Service Corpus Christi TX
1001 PM CDT Wed Sep 27 2017 .DISCUSSION... Just made a few adjustments. Persistent convection over Duval County near frontal boundary/convergence area is slowly weakening, but may last another two hours or so before becoming lighter in nature. Still kept the likely POPs for the western areas as could have some more development overnight. However, winds at Laredo and Cotulla have become more NE than E this evening and if winds do not become more easterly overnight, then rainfall may be more limited there (which would be OK since that area has seen plenty as of late). HRRR is pretty clueless on handling convection out to the west (last couple hours of runs have a much more coverage now), so will have to rely on old-time forecasting in part, using surface data/analysis and satellite trends (which still show cooling tops in Mexico). Overall, changes were made based on radar and observation trends and needs. && .PREVIOUS DISCUSSION... /Issued 550 PM CDT Wed Sep 27 2017/ DISCUSSION... See AVIATION discussion for 00Z TAFS. AVIATION... Will keep this short. Basically the best chance for convection will be in the Laredo (KLRD) terminal, where showers will begin no later than 02Z and likely continue off and on through a good part of the night. Farther east, less activity expected this evening and main convection mentioned in terminals is during the daytime on Thursday (do have a TEMPO SHRA at KALI). Most of the convection will be late morning and afternoon, spreading west by late afternoon toward the KLRD terminal again. Outside of convection should have VFR conditions for the most part, with a potential for some light (MVFR) fog at KVCT and KALI toward morning (although overcast deck will limit radiational cooling). Mainly east winds this evening become light northeast overnight and should be mainly NE or E through Thursday, with winds expected to remain 11 knots or less outside of convection. PREVIOUS DISCUSSION... /Issued 333 PM CDT Wed Sep 27 2017/ SHORT TERM (Tonight through Thursday Night)... Due to saturated soil across the 4 western counties, any additional rainfall may lead to more flooding. Thus, have expanded the Flash Flood Watch to include Duval and McMullen and extended it through 12Z Thu morning. Convective activity has increased once again this afternoon across the CWA. Kept the higher pops across the western CWA tonight as mid level drying is expected across the eastern CWA. This is in response to mid level high pressure, currently centered over the NW Gulf, moving slightly farther west tonight/Thu. Kept the highest rain chances across the western CWA tonight and Thu due to continued deeper moisture and proximity to embedded upper level short wave, however QPF values are expected to be much less by Thu. This is due to a little more drying in the 800mb- 600mb levels working its way into the western areas by Thu, but very saturated above that. Thus am expecting the convection to become more elevated overnight into Thu, possibly becoming more elevated stratiform with time. For now have gone with mention of mainly shra`s and iso tsra`s through the period. At the sfc, the CWA is currently sitting between a sfc high to the north and low pressure to the southeast over the gulf. This will lead to a more northeasterly flow tonight and Thu, which will provide some low level moisture convergence across the eastern CWA tonight and Thu, which is expected to produce iso low topped -shra`s. Therefore, kept a 20 pop across the east and over the gulf waters despite the high pressure/drying aloft. Cooler temps expected tonight through Thu night due to the clouds and abundant moisture. LONG TERM (Friday through Wednesday)... The closed/cut-off mid-level low to our west finally begins to break down and lift northward at the start of the long term period. Ridging moves back into the region by the weekend though the flow aloft looks more progressive for the start of work week which could mean more unsettled weather possible. Weak cold front will be inching closer to the region on Friday and Saturday but with large PWATs still in place we will continue to see scattered shower and thunderstorm activity. Expecting a marker decrease in coverage by Saturday mostly confined to the southern areas of the CWA in closer proximity to the frontal boundary. Behind the boundary there will be some drier air filtering into the region so we can be thankful for that, however, PWATs are expected to still be slightly above average in the 1.5-1.8" range, but definitely better than the 2+" we`ve got going now. This respite is brief which is unfortunate with another slug of moisture, possibly 2+" moving back into the region by Tuesday. With the influx of more moisture isolated to scattered convection is possible Monday through Wednesday and mostly driven by seabreezes and coastal convergence. Back to summer we head... && .PRELIMINARY POINT TEMPS/POPS... Corpus Christi 76 87 74 89 72 / 30 30 20 30 20 Victoria 73 87 72 88 68 / 20 40 30 40 10 Laredo 75 86 73 87 71 / 60 50 50 40 30 Alice 74 88 72 90 70 / 50 30 20 30 20 Rockport 76 87 76 88 74 / 20 30 20 20 20 Cotulla 72 86 72 88 69 / 60 40 50 30 20 Kingsville 75 89 73 91 72 / 40 30 20 30 20 Navy Corpus 79 87 77 88 76 / 20 30 20 20 20 && .CRP WATCHES/WARNINGS/ADVISORIES... TX...Flash Flood Watch until 7 AM CDT Thursday For the following zones: Duval...La Salle...McMullen...Webb. GM...None. && $$ GW/86...SHORT TERM
Please see the 00Z aviation forecast discussion below.

AVIATION... Light to moderate rain continues over a good portion of south central Texas this evening, with the most persistent activity from SAT/SSF west toward DRT. We will continue to mention light to occasional moderate rain in the forecast for the evening and overnight hours. Otherwise, look for a gradual lowering of ceilings overnight with MVFR expected at AUS and upper end IFR for our remaining TAF sites. Gradual improvement is expected tomorrow afternoon. PREV DISCUSSION... /ISSUED 248 PM CDT Wed Sep 27 2017/ SHORT TERM (Tonight through Thursday Night)... A complex rainfall situation is setting up across the western half of the CWA this afternoon and evening. A combination of continued rich low level moisture advection, an approaching frontal boundary, and a mesoscale convective vortex will all come into play to continue the flash flood threat through tomorrow. Through the rest of the afternoon, while the majority of the heavy rainfall continues to develop well west of the I-35 corridor. Increased instability and another surge of low level moisture is pushing north from South Texas and resulting in isolated thunderstorm development. While this activity is mostly isolated in nature, CG lightning observed in the updrafts and significantly colder cloud tops indicate the possibility for intense downpours with the added low to mid level CAPE available. While these should weaken as they approach and are currently moving north rather quickly, they will still have the capability of dropping up to 2 inches of rain in an hour or two, which could exceed the very low flash flood guidance in Atascosa County, and to a lesser extent Bexar County. With this short term concern for localized flash flooding, it was decided to expand the flash flood watch to include both Atascosa and Bexar counties. After midnight, the MCV is progged to continue to shift northwestward, as evidenced in both hi-resolution guidance and in the GFS/ECMWF. This should focus the heavier rainfall potential overnight to Del Rio and Val Verde County. Thus, QPF was increased in these regions along the Rio Grande and for Val Verde. PoPs will begin to decrease overnight for the eastern areas as the aforementioned isolated activity wanes due to a lack of diurnal heating. Through Thursday, models continue to generate moderate to heavy rainfall over the extreme western areas of the CWA, with lighter rates from Uvalde and east. While there may be a drop off in precip coverage tomorrow over the eastern half of the flash flood watch, it may be worth maintaining through Thursday evening as currently issued due to rainfall amounts unofficially exceeding 20 inches in some spots in Zavala and Dimmit counties. LONG TERM (Friday through Wednesday)... Precip chances begin to decline beginning overnight Thursday and through Friday. Over the weekend, the parent low over the four corners currently will lift northward and take the upper level support with it, dramatically decreasing our chances for rain. A more typical late September, early October pattern will then take its place by early next week. By mid week, an elongated ridge axis will broaden over the state according to the ECMWF resulting in slight chances for rain, mainly over the southern and southeastern areas where better moisture resides. However, no hazards are expected. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 71 84 69 82 65 / 40 50 50 30 20 Austin Bergstrom Intl Airport 71 84 69 82 64 / 40 50 50 30 20 New Braunfels Muni Airport 71 84 69 84 65 / 40 50 50 30 20 Burnet Muni Airport 67 80 65 77 61 / 50 60 60 40 20 Del Rio Intl Airport 68 77 69 80 66 / 70 70 60 60 20 Georgetown Muni Airport 69 83 66 80 62 / 50 50 50 30 10 Hondo Muni Airport 69 85 70 86 65 / 60 50 50 40 20 San Marcos Muni Airport 70 84 69 83 64 / 40 50 50 30 20 La Grange - Fayette Regional 72 87 70 85 66 / 20 40 50 30 10 San Antonio Intl Airport 70 84 70 84 66 / 40 50 50 30 20 Stinson Muni Airport 71 84 71 84 67 / 40 50 50 30 20 && .EWX WATCHES/WARNINGS/ADVISORIES... Flash Flood Watch through Thursday evening for the following counties: Atascosa...Bandera...Bexar...Dimmit...Edwards...Frio... Kerr...Kinney...Maverick...Medina...Real...Uvalde...Val Verde... Zavala. && $$ Mesoscale/Aviation...24 Synoptic/Grids...LH Public Service/Data Collection...YB
Area Forecast Discussion...UPDATED
National Weather Service Fort Worth TX
747 PM CDT Wed Sep 27 2017 .AVIATION... /00Z TAFs/ North flow will continue with occasional showers. Potential for stratus Thursday morning. A cold front bisects Central and East Texas, and the surface boundary is now beyond all of our TAF sites. Instability remains above the shallow frontal inversion, and despite the easterly trajectories of the associated parcels, the moisture flux has been extraordinary. While this advection may continue, a spoke of energy swinging through western portions of North Texas will likely be the primary focus for convection overnight, which should remain west of the TAF sites. Cooling near the base of the frontal inversion could result in some MVFR (or even IFR) ceilings Thursday morning, a process that may be made more effective where rain has already cooled/ saturated the boundary layer. This will be most pronounced across western portions of North Texas, and the current TAFs maintain VFR conditions. However, based on temp/moisture trends this evening, a TEMPO for stratus may be needed for the daybreak to mid-morning period. This could be introduced with the 03Z amendments. Showers will likely redevelop above the frontal layer Thursday afternoon, primarily impacting Central Texas. 25 && .SHORT TERM... /Issued 244 PM CDT Wed Sep 27 2017/ /Through Tonight.../ A fairly well-defined moist-axis is present this afternoon roughly bisecting our CWA in half from northeast to southwest--associated with the 925-850 mb front. Near and ahead of this axis, we`re seeing continued isolated to scattered shower development where some insolation has allowed for diurnal gains in instability. These individual cores have been pretty efficient rainfall producers, but are localized and moving just enough to keep the flood threat low. That said, any cells which manage to sit or train over the same area will be capable of laying down 1-2 inches of rain over an hour or so, and this could lead to some runoff issues in poor drainage areas/low spots. Most of this activity should begin to diminish with the loss of heating this evening. For tonight, it appears that the most focused ascent may actually begin to weaken a bit as the primary area of low pressure begins to lift northeastward into the Four Corner`s Region. As a result, we`ll cap PoPs at 50% overnight across our western counties. Isentropic charts from the RAP show a decent push of upglide atop the frontal inversion materializing late tonight across our northwestern counties. As a result, have nudged PoPs upwards just a bit here from the previous forecast. We`re not anticipating widespread flooding issues given the fairly localized nature of any of the heavier rainfall, but some locales have received upwards of 2-3 inches of rain over the last 24 hours, and additional rainfall could result in some minor flooding of low spots. Carlaw && .LONG TERM... /Issued 244 PM CDT Wed Sep 27 2017/ The upper level trough responsible for pushing a cold front across North and portions of Central Texas will slowly move to the east during the day on Thursday. The cold front, however, is expected to make little progress and linger somewhere around a Hillsboro to Hamilton line. Given the shallow nature of the cool air and south/southeasterly winds aloft, isentropic lift will aid the development of showers and isolated thunderstorms during the afternoon on Thursday and Friday. The highest rain chances will be west of a Stephenville to Gatesville line both days as large scale lift remains truncated west of our area. With weaker forcing across the I-35 corridor, expect to see less coverage the farther east you go. A reinforcing short of slightly cooler and drier air will move in Friday morning and afternoon, leading to a gradual decrease in precipitation coverage from northwest to southeast. The dry air will remain in place through the rest of the weekend, leading to dry and comfortable conditions as upper level ridging moves overhead. A more zonal pattern will begin Sunday night as another trough makes its way across the Central Great Plains. High temperatures will remain steady Monday through Thursday with no major weather pattern shifts across the area. Highs are expected to be in the mid 80s to low 90s everyday with lows in the 60s, except for low 70s in urban locations. Hernandez && .PRELIMINARY POINT TEMPS/POPS... Dallas-Ft. Worth 69 83 65 80 64 / 30 30 30 30 10 Waco 70 85 65 81 61 / 30 40 40 40 10 Paris 67 83 63 81 61 / 30 20 0 10 10 Denton 64 80 62 78 58 / 30 30 30 30 20 McKinney 66 83 63 80 59 / 30 20 20 20 10 Dallas 69 84 66 81 65 / 30 30 20 20 10 Terrell 70 86 66 82 61 / 30 20 10 20 10 Corsicana 71 87 66 84 63 / 30 30 20 20 10 Temple 70 83 65 80 61 / 30 50 50 40 20 Mineral Wells 63 76 62 75 57 / 40 50 30 40 20 && .FWD WATCHES/WARNINGS/ADVISORIES... None. && $$ 25/05
Area Forecast Discussion
National Weather Service Houston/Galveston TX
923 PM CDT Wed Sep 27 2017 .UPDATE... West to southwest flow aloft over the western half of Texas and upper ridging over the eastern half will keep best rain chances well west (but not completely out of) of the region tonight. Through midnight, expect showers to continue to skirt the western counties from ongoing activity across Central and South Central Texas. Another round of isolated showers is also possible for the extreme eastern counties as what appears to be a weak surface boundary/wind shift stretching from northeast Texas towards the Louisiana coast nudges eastward. Regional radar mosaic shows a few showers already attempting to develop along this boundary, with high resolution guidance indicating this trend for isolated showers will continue through the remainder of the evening hours and possibly into the overnight period. Have updated rain chances to account for this as well as temperatures and dew points based on latest observational trends, with morning lows again forecast to be in the 70s inland and near 80 along the coast under partly to mostly cloudy skies. Huffman && .PREV DISCUSSION... /ISSUED 749 PM CDT Wed Sep 27 2017/ AVIATION... Seabreeze moving past IAH and showers waning quickly. Mid and high clouds will stream into the area from the southwest with subsidence and drying becoming greater influence the further east the clouds move. VFR conditions expected overnight at most TAF sites. Possibly some patchy fog/MIFG for CXO near sunrise but cloud cover should minimize the threat so have opted to hold off on mentioning in current TAFS. Showers possibly moving into the CLL area around midnight but will wait to see if some of the more rain generous model solutions are on track at 03z before adding to CLL. Scattered showers again develop around 18-19z and continue into the late afternoon hours. Northern areas may be drier with the bridging of the northeasterly flow. 45 PREV DISCUSSION... /ISSUED 248 PM CDT Wed Sep 27 2017/ DISCUSSION... Radar imagery shows a few showers in Jackson, Wharton, and Matagorda counties this afternoon, currently over the pocket of higher moisture as seen on the GOES-16 satellite imagery. Not expecting much in terms of coverage tonight, but kept widely scattered showers and thunderstorms in the forecast to continue into the early evening. Short term guidance such as the HRRR and RAP are hinting at some isolated shower development in the eastern zones of the forecast area early Thursday morning. By Thursday afternoon, PW values increase to 2.00-2.20 inches, so moisture will be in surplus. Additionally, diurnal heating and lift provided from both the seabreeze and stationary/ "cool" front as it sags southward into the region, will provide a better chance scattered shower and thunderstorm development Thursday. Kept precip in the forecast for Friday as well, with less coverage in comparison to Thursday. High temperatures for the rest of the week will be in the upper 80s to lower 90s, with lows in the mid 60s to upper 70s along the coast. Besides the possibility of a few isolated lingering showers late Friday into early Saturday, not expecting much in terms of precip through the weekend. Weak upper level ridging attempts to build in behind the frontal boundary. More seasonable weather can be anticipated Saturday and Sunday with lower dew points, as drier air ushers in behind the weak front. Temperatures will also be a tad cooler and closer to normal for this time of year. With the rise in PWs ranging from 1.40 to 1.70 inches beginning Monday, a more summer-like pattern will return to the forecast. Winds will shift back to out of the southeast with the start of the new week, and as a result carrying scattered showers and thunderstorms associated with diurnal/seabreeze activity. Conditions look to dry out by mid-next week as both the ECMWF and GFS begin to build in an upper level ridge over the region. This area of high pressure will enhance subsidence (sinking air), so therefore holding PoPs at 30% or lower through the remainder of the week. High temperatures will rise into the mid to upper 80s, with lows falling into the upper 60s inland to upper 70s closer to the water. Hathaway MARINE... Generally light to moderate east to southeast winds and seas around 1 to 3 feet will persist through tonight. Tomorrow winds become more northeasterly ahead of an approaching frontal boundary, which will finally push through the waters by the end of the week. Northeast winds will become more moderate with slightly elevated seas in the wake of the front, and caution flags may be required at times over the weekend. The pressure gradient tightens once again and induces moderate easterly to occasionally northeasterly winds and building seas heading into the middle of next week. This, combined with already above normal tides, may cause some minor coastal flooding issues mid to late week next week. 11 && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 73 91 70 88 66 / 20 30 40 20 10 Houston (IAH) 75 90 72 90 68 / 20 20 30 10 10 Galveston (GLS) 80 89 79 90 77 / 20 20 20 20 10 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ Discussion...14
Area Forecast Discussion
National Weather Service Melbourne FL
925 PM EDT Wed Sep 27 2017 .UPDATE... Tonight...The area remains in a weak pressure pattern/col at the surface, while an upper level low remains anchored over the eastern Gulf of Mexico. Boundary driven convection this afternoon/early evening occurred a little farther to the south compared to yesterday, and propagated southward. The east/west boundary collision is occurring near Lake county and so far only a few cells have formed. The HRRR and local WRF confine limited convection to areas mainly west of the Kissimmee River. Therefore, we are not planning on a small cluster of convection going well into the overnight again. Will monitor radar a little longer before updating the forecast to remove small PoPs across the south. && .AVIATION...Conditions will continue primarily VFR through Thu. The 18z GFS generated precip Thu afternoon in the same general area as today, inland from KVRB-KFPR-KSUA. && .MARINE... Tonight-Thursday...Gradient winds continue very light, less than 10 knots and occasionally less than 5 knots, as a weak pressure pattern/col exists over the waters. Northeast swells persist but are now 5 feet or less at 41009. The wave models hold onto 6 foot seas through Thu, but with little wind wave action, the only real mariner hazard will continue to be near inlets during the outgoing tide. In these situations an exercise caution statement would really be most needed in the nearshore zone around inlets/shoals. The Gulf Stream current doesn`t steepen northeast swells the same way that northeast wind waves are steepened. Bottom line, will remove exercise caution statements. && .HYDROLOGY...(Previous Discussion) A River Flood Warning remains in effect for the St Johns River near Cocoa, above Lake Harney near Geneva, near Sanford, near Deland and at Astor. River levels will remain high over the middle St Johns River Basin, with only a very slight decline into early next week. && .CLIMATE...Record highs for Thursday... THU (9/28) DAB 92 1974 MCO 98 1921 SFB 94 1980 MLB 95 1976 VRB 93 1974 FPR 95 1942 && .MLB WATCHES/WARNINGS/ADVISORIES... FL...None. AM...None. && $$ Lascody/Johnson