Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 05/19/19

Area Forecast Discussion
National Weather Service Bismarck ND
943 PM CDT Sat May 18 2019 .UPDATE... Issued at 939 PM CDT Sat May 18 2019 Trends and CAM models support cancelling the northern counties of the winter weather advisory for Golden valley, Billings, and Stark. Snow continues across the southern four counties and will keep the advisory there through tonight. Widespread rain continues south central and southeast this evening, and will slowly diminish overnight as teh upper low moves east. UPDATE Issued at 638 PM CDT Sat May 18 2019 Latest RAP model places the h500 closed low over southwest South Dakota at 6 PM CDT and forecast to drift slowly east during the next 18 hours. This will maintain the weak deformation zone aloft over the region and precipitation tonight. Isentropic analysis suggests the best lift should trend slowly south with time so expect some improving conditions and drying across portions of central and northern North Dakota. The best precipitation chances remain south tonight. Snow will remain likely across the southwest through this evening, diminishing slowly overnight. Current forecast looks ok. && .SHORT TERM...(This evening through Sunday) Issued at 335 PM CDT at May 18 2019 With low pressure surface and aloft to the south of the forecast area, bands of precipitation continue to rotate into North Dakota. Snow in the southwest continues where surface temperatures were in the lower 30s. Have extended the winter weather advisory for southwest North Dakota until 6 AM Mountain time. Will expect accumulations to vary from the lower elevations near 3 inches to the higher terrain 5 inches. The rest of the area will have rain showers. Radar trends have been that the steady rain was diminishing and batches rotating in were more showery in nature. As the low lifts northeast the showers of rain and snow will slowly end from north to south and should be completely ended by mid morning Sunday. Sunday actually looks like a decent day weather wise, relatively speaking and as compared to the last two days. Drier air will work in for at least some sunshine and with that, temperatures into the 50 over all but snow covered ground. That too, though will be quick to melt off and may not negatively impact temperatures as much as I have indicated in the forecast. .LONG TERM...(Sunday night through Saturday) Issued at 335 PM CDT Sat May 18 2019 With weak ridging on Monday that will provide for sunshine and closer to normal high temperatures. That comes, though, after a cold morning with the risk of at least areas of frost. This will be a challenge in posting a headline for as if there is still snow on the ground in the southwest a frost advisory would seem counter intuitive. By Monday night the next upper low pushes toward the state with significant rains, on the order of an inch or two, for the Tuesday and Wednesday period. Again as with this last system, the northern border counties will get the least amount of rain. This area, the north, is where rain is needed. This system is not as cold so the expectation at this point is for liquid precipitation. Unsettled showery weather may continue into the end of the week with that cool pool of air over us in the form of the mid level low. A system for next weekend looks to bring chances for storms but not this steady all day type rain. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 638 PM CDT Sat May 18 2019 A large and slow moving spring storm will bring widespread precipitation to the Northern Plains. For North Dakota the precipitation will remain across the south with VFR conditions from KISN-KMOT. Rain is expected across southern North Dakota tonight with snow across the southwest. IFR to LIFR KDIK, improving to MVFR after 13z. MVFR to VFR KBIS-KJMS in light rain. && .BIS WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory until 6 AM MDT Sunday for NDZ040-041-043- 044. && $$ UPDATE...WAA SHORT TERM...JPM LONG TERM...JPM AVIATION...WAA
Area Forecast Discussion
National Weather Service Dodge City KS
804 PM CDT Sat May 18 2019 .UPDATE... Issued at 805 PM CDT Sat May 18 2019 Cancelled severe thunderstorm watch #186 early. Kept Barber county in the watch for awhile, as the warm sector hangs on through 9 pm. Elsewhere, a decaying MCS with stratiform rain and outflow winds continues to fizzle across the CWA. Some reports of severe weather this evening included 2 inch hail near Meade and wind gusts near 60 mph near Sublette. && .SHORT TERM...(This evening through Sunday) Issued at 300 PM CDT Sat May 18 2019 A strong upper level disturbance will pass across western Kansas this evening. Thunderstorms can be expected and some of these will be severe with large hail and high winds. Instability is much lower than yesterday across most of western Kansas, although there is still moderate instability across south central Kansas. Although it is much drier across southwestern Kansas, it is also colder at upper levels than yesterday so that severe hail is expected with the strongest storms. .LONG TERM...(Sunday night through Saturday) Issued at 300 PM CDT Sat May 18 2019 After a quiet day Sunday, an intense upper level disturbance will gradually approach western Kansas Sunday night and move across the plains by Monday night. A front over the southern plains will likely stay to the south of the Kansas state line, which means that the high-end severe weather would be to the south. Widespread rain and embedded thunderstorms with locally heavy rain can be expected north of the front in the cool air. A flood watch may be required in parts of south central and southwestern Kansas. After a quiet Tuesday and Wednesday, other strong upper level storm systems are expected to approach by Thursday and then over the weekend. High instability will be in place across much of the southern and central plains given the warm and humid air mass so that a few rounds of severe thunderstorms are expected. The exact locations of the severe weather is not known this far out, but there is the potential for high end severe. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 445 PM CDT Sat May 18 2019 A strong progressive shortwave trough will race through SW KS this evening, producing scattered convection. Included convective TEMPO groups for all airports this evening, using HRRR as guidance. Strong subsidence will quickly take over after 06z Sun behind the departing shortwave with a clearing sky. Associated cold front will bring strong N/NW winds for several hours this evening, gusting near 30 kts, followed by rapidly diminishing winds through Sunday morning. && .PRELIMINARY POINT TEMPS/POPS... DDC 48 72 50 61 / 40 0 30 80 GCK 44 71 49 59 / 50 0 40 80 EHA 44 75 53 68 / 10 0 50 60 LBL 45 74 54 67 / 20 0 70 80 HYS 48 68 45 56 / 70 0 10 80 P28 53 74 53 65 / 50 0 10 80 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Turner SHORT TERM...Finch LONG TERM...Finch AVIATION...Turner
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1025 PM EDT Sat May 18 2019 .SYNOPSIS... Afternoon showers and thunderstorms are expected across the mountains through Sunday. Thunderstorm coverage may increase Monday as a weak cold front crosses the forecast area. Following the front, a strong summer-like ridge of high pressure will build across the Deep South resulting in well above normal temperatures with limited rainfall persisting through next Friday. && .NEAR TERM /THROUGH SUNDAY/... As of 1025 PM EDT Saturday: Quiet weather with clearing skies observed across the forecast area late this evening. Have adjusted temperatures down a bit to match latest trends. Still looking like any fog that forms will be confined to mountain valleys, and more than likely only the most fog prone valleys. Otherwise, ridging will continue to dominate the Southeast through the near-term, as a trough over the Plains pushes a front toward the area, progged to be on our doorstep at the end of the period. Bermuda high over the western Atlantic sill keep a south to southeasterly low-level flow across the area, with well above-normal temperatures continuing, a good 8-10 degrees warmer than normal for highs and lows through the near-term. The upslope low-level flow will allow for some mechanical lift over the terrain with orographic upglide, and despite the upper ridge bringing a bit of a subsidence inversion at about 500-600mb, there will still be enough CAPE (generally between 1000-2000 J/kg out there now, could see a bit higher through the afternoon) that isolated convection is expected this afternoon. Naturally the primary location will be over the mountains, but HRRR and other CAMs are pointing to some convection over the Piedmont too. Gusty winds and brief heavy rains would be the main threats along with lightning, and generally don`t see a lot of support for any severe concerns. SPC General Thunder looks good. As we move into Sunday, dry air ahead of the front as well as continued mid-level warming will limit convective concerns, but isolated mountain showers and thunderstorms will be possible (SPC General Thunder for about the NW half of the area). Overall very little change in afternoon highs going into Sunday, at best maybe a couple of degrees lower than what we`ll see this afternoon. && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/... As of 135 PM Saturday: A weak cold front will impinge upon the NC mtns Sun night. This front will have little ulvl support outside of a passing and decaying h5 shortwave. Cross sections show omega limited to the llvls associated with weak sfc convg and some mech lift. Don/t expect much more than isol -shra thru daybreak...but instability will rise enuf for sct tstm development mainly across the mtns, fthills and NC piedmont during the afternoon and early evening. Shear levels remain on the low these storms will likely remain in a general pulse mode. The frontal zone pushes east of the FA arnd 00z and no lingering activity is expected Mon night nor through the day Tue as heights rise in response to a developing large-scale h5 ridge over the deep south. Max and min temps will remain arnd 8-10 degrees abv normal each day and night. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... As of 200 PM Saturday: High confidence is had in the ext range fcst. The latest guidance agrees well on the development and persistence of a strong sub-trop high encompassing the SE region thru the period. The best chance for any convec will be across the mtns...where pockets of stronger thermals may actually overcome a stg llvl cap and sbCIN to tap into a layer of instability abv h5. This possibility remains low given the overall suppressive synoptic will keep pops limited to isol and diurnal in nature. Max temps will be the big story as temps remain abt 8-10 degrees abv normal Wed and likely rise to arnd 10-14 degrees abv normal by the weekend. With sw/ly BL flow persisting...sfc td/s wont mix out too much...which will be a good thing for fire danger issues. However with td/s remaining in the 60s...there will be an increasing heat index concern outside the mtns Thu/Fri/Sat afternoons. Mins will remain quite warm as well with lows in the L60s to arnd 70 F each morning. && .AVIATION /03Z SUNDAY THROUGH THURSDAY/... At KCLT and elsewhere: VFR conds expected to prevail thru the period at TAF sites with only a 20 percent chance of MVFR BR at KAVL and KHKY. Isolated shra/tsra possible beginning as early as 17Z, focused across the mountains with a 15 percent chance of impacting KAVL. Outlook: Mountain valley fog will be possible each morning through early next week, with diurnal focused showers and thunderstorms possible each day through Monday. Confidence Table... 02-08Z 08-14Z 14-20Z 20-00Z KCLT High 100% High 100% High 100% High 100% KGSP High 100% High 100% High 100% High 100% KAVL High 100% High 100% High 100% High 100% KHKY High 100% High 100% High 100% High 100% KGMU High 100% High 100% High 100% High 100% KAND High 100% High 100% High 100% High 100% The percentage reflects the number of guidance members agreeing with the scheduled TAF issuance flight rule category. Complete hourly experimental aviation forecast consistency tables and ensemble forecasts are available at the following link: && .GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...None. SC...None. && $$ SYNOPSIS...SBK NEAR TERM...Munroe/TDP SHORT TERM...SBK LONG TERM...SBK AVIATION...Munroe
Area Forecast Discussion
National Weather Service Houston/Galveston TX
1025 PM CDT Sat May 18 2019 .DISCUSSION... Have seen a series of strong to severe thunderstorms moving across northern Houston county. The severe threat from now until the early morning hours is expected to be basically the just issued tornado watch area. The cap has held strong for most of the area this evening, but expect thunderstorm coverage to increase overnight generally NW of a Madisonville to Conroe to Liberty line. 33 && .PREV DISCUSSION... /ISSUED 634 PM CDT Sat May 18 2019/ AVIATION... A cluster of strong thunderstorms over North Texas will probably clip the part of SE TX this evening. Not sure if they will impact either KUTS or KCLL but will carry a TEMPO for thunder through 02z just in case. Will carry a VCSH elsewhere tonight as capping looks to be holding and Amdar soundings still show a bit of a cap at 700 mb. The 18z GFS and the 21z HRRR did not initialize well and their respective solutions of storms making to Houston looks somewhat suspect. A mix of IFR/MVFR ceilings expected overnight. Cigs will scatter out Sunday afternoon with VFR conds expected between 18-21z. 43 .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 72 89 73 89 73 / 50 10 10 10 10 Houston (IAH) 75 89 75 89 76 / 60 30 10 10 10 Galveston (GLS) 77 82 77 83 78 / 40 20 10 10 10 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...Coastal Flood Advisory until 8 PM CDT Sunday for the following zones: Brazoria Islands...Galveston Island and Bolivar Peninsula...Matagorda Islands. GM...SMALL CRAFT SHOULD EXERCISE CAUTION until 4 AM CDT Sunday for the following zones: Coastal waters from Freeport to Matagorda Ship Channel TX out 20 NM...Coastal waters from High Island to Freeport TX out 20 NM...Galveston Bay... Matagorda Bay. Small Craft Advisory until 4 AM CDT Sunday for the following zones: Waters from Freeport to Matagorda Ship Channel TX from 20 to 60 NM...Waters from High Island to Freeport TX from 20 to 60 NM. && $$ Discussion...33
Area Forecast Discussion
National Weather Service Huntsville AL
1036 PM CDT Sat May 18 2019 .NEAR TERM...(Rest of tonight) Issued at 1035 PM CDT Sat May 18 2019 Regional radar indicates that an outflow dominant QLCS continues to push further east into western TN and north central MS. This is farther east in expectation than recent HRRR runs and the 18Z NAM/GFS. The line should encounter a much drier and capped airmass as noted in our earlier evening update. But can`t ignore the current radar and have opted to add a low PoP of showers tonight in our far western portion of the forecast area (NW AL/Shoals area). .SHORT TERM...(Sunday through Monday night) Issued at 310 PM CDT Sat May 18 2019 The overall wx pattern is xpcted to turn a little more active going into the second half of the weekend period. An upper trough axis over the mid Plains states is xpcted to pivot NE into the Great Lakes on Sun. As this occurs, a sfc low will also move thru the Great Lakes states, dragging a weak frontal boundary ewd into the Mid South/lower MS Valley regions. As the sfc low continues to lift to the NE, the front will also translate ewd late Sun into Sun night. Sfc flow ahead of the front may be a little strong, as evidenced by an H85 jet out of the SSW near 40-50kt early Sun. This may translate into gradient wind gusts around 30 MPH Sun morning in the higher elevations of NE AL. Low level convergent flow along the front itself may result in a few strong tstms Sun afternoon into Sun night capable of brief wind gusts to 50 MPH. The front is then xpcted to stall invof the area, with a few showers/tstms remaining possible into the day Mon. Even with the front settling into the area, overall temps look to trend unseasonably warm, given a weak upper ridge pattern remaining in place over much of the Gulf region. Afternoon highs Sun/Mon look to remain in the lower/mid 80s while overnight lows trend in the lower/mid 60s for most locations. .LONG TERM...(Tuesday through Friday) Issued at 310 PM CDT Sat May 18 2019 At the beginning of the long term portion of the forecast on Tuesday morning, sfc high pressure will be situated to our north while another strong low pressure system will be taking shape well to our west over the central High Plains. As the sfc high to our north shifts eastward, flow will begin to back from the east and then south during the morning. A strengthening low-lvl temperature gradient will give rise to warm frontogenesis, but this is likely to take place just to our north. Although, there is still some uncertainty in the location of the developing warm front. Nevertheless, an axis of generally weak confluence will be present over the area during the morning into the afternoon. Global models also indicate a weak upper shortwave translating SSW-NNE across the area along the western flank of a building upper ridge. Although broad scale forcing will be generally low, some showers and thunderstorms may develop in the moderately unstable environment. A slight chance POP was thus introduced into the forecast for Tuesday afternoon. Otherwise, the long term portion of the forecast will be dominated by a highly amplified pattern across the CONUS with a deep trough in the West CONUS and a strong upper ridge situated over the East CONUS from Wednesday into next weekend. This will bring generally dry and hot weather to the TN Valley region during the period. Given the general agreement among the suite of global and ensemble guidance, this is a fairly high confidence forecast for the period. As stated in the previous long term discussion, GEFS probabilities indicate high confidence that 500 mb heights will exceed 2 standard deviations above the mean for this time of year across our area. What does this mean? Well, good confidence in above normal temperatures. While the guidance suite shows a range of temperatures generally in the mid 80s to lower 90s. Given the anomalous nature of the situation, the actual forecast high temperature values were placed above the main part of guidance, with values reaching into the mid 90s at some locations for Thursday through Saturday. Based on some of the data, temperatures even reaching the upper 90s would appear possible. Record high temperatures during this period are mainly in the mid 90s, so some records could be broken. While there is high confidence in the broad scale strong upper ridge, a few small showers or storms could occur each afternoon during the period. However, given the general limitation for broad scale ascent, any convection will largely be driven by very localized effects...potentially sfc temperature/moisture gradients. Anyway, the risk for showers and thunderstorms currently is too low to place POPs in the forecast, but will mention here for now. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 525 PM CDT Sat May 18 2019 VFR flight weather conditions are expected through tonight into Sunday morning. Southerly flow will increase markedly by 14Z with sustained speeds of 12-17kt and gusts of 22-25kt. An area of showers and a few thunderstorms will arrive in northwest AL including KMSL as early as 14Z, but more likely 17-21Z. It is much less certain if these will reach the KHSV area due to a more stable and drier airmass further east, but have maintained VCSH after 19Z. && .HUN WATCHES/WARNINGS/ADVISORIES... AL...NONE. TN...NONE. && $$ NEAR TERM...17 SHORT TERM...09 LONG TERM...KDW AVIATION...17 For more information please visit our website at
National Weather Service Jackson KY
1040 PM EDT Sat May 18 2019 .UPDATE... Issued at 1040 PM EDT SAT MAY 18 2019 Just a quick update to drop the thunder chances and most of the PoPs overnight. Also fine tuned the sky cover and incorporated the latest obs/trends into the T and Td grids. These have been sent to the NDFD and web servers. UPDATE Issued at 800 PM EDT SAT MAY 18 2019 23z sfc analysis show high pressure off to the east with low pressure found to the west and north. The high has kept eastern parts of the area quiet this evening while a band of showers and thunderstorm rode north northeast through our western counties. A few of these storms became strong with gusty winds, heavy downpours, and frequent cloud to ground lightning the main threat. Look for these to dissipate shortly with the lack of heating - though a few bonus cells may make it into far southeast Kentucky from Virginia over the next hour or so. Temperatures surged today toward 90 degrees across the area with readings back down toward the low 80s currently most places - though cooler where it rained. Dewpoints, meanwhile, are generally from 60 to 65 degrees across the area and winds have settled to light and variable most places. Have updated the grids to fine tune the convection dissipating over the next few hours and to hit fog a little harder in places that had rain. These updates have been sent to the NDFD and web servers. An updated HWO and ZFP will be sent once the thunder dies out - within the hour. && .SHORT TERM...(This evening through Sunday night) Issued at 310 PM EDT SAT MAY 18 2019 Visible satellite imagery shows a cumulus field across the entire area at mid afternoon. The most enhanced area of cumulus is across the southwest part of the forecast area, which is where multiple runs of the HRRR have consistently developed convection today. Timing for initial development of isolated to scattered showers/storms still looks to be 20-21Z. The isolated/scattered convection should develop northeast, but with loss of daytime heating any showers and thunderstorms will quickly die, and will end shower/storm chances at 00Z. Any lingering cloud from late afternoon convection will dissipate and skies should be mostly clear tonight. Dewpoints are lower than yesterday, and valleys will decouple again tonight, so should see at least a ridge valley temperature split develop, and this has been depicted in the NDFD with valley minimums upper 50s to lower 60s, and thermal ridges more in the mid and upper 60s. River valley fog should also develop again tonight. On Sunday low level wind fields will increase in advance of a cold front that should be approaching western KY by 00Z Monday. 925mb and 850 mb winds around 40 knots are forecast into the western part of the forecast area. Our wind gusts will depend on the amount of mixing, but definitely could see some gusts to 35 mph in the western part of the area. Shower and storms are expected to develop ahead of the cold front approaching KY, but best low level wind fields and upper level support will remain to the west, and especially northwest of our area, in line with SPCs Day 2 Convective outlook. Most likely scenario is for one or two bands of showers and storms to move across eastern KY late Sunday and Sunday night, with the intensity of the convection decreasing as it moves into and across our area. Sunday will feature another day with above normal temperatures and highs mostly in the mid to upper 80s. .LONG TERM...(Monday through Saturday) Issued at 310 PM EDT SAT MAY 18 2019 The extended is reminiscent of a summer type pattern. Models appear to be in good agreement with main synoptic features. Aloft, strong ridging will eventually develop over the southeast CONUS resulting in a warming trend through the upcoming week. Any threats of rain will be limited to isolated to widely scattered, mainly afternoon and early evening convection. A lobe of energy associated with a low lifting northward through the Great Plains (and surface warm frontal boundary at the surface) does ride up the western side of the developing ridge Tuesday and Tuesday night. Thereafter ridging dominates the pattern until it is flattened by a northern stream short wave passing through the Great Lakes by the end of the period, Friday night into Saturday. Closer to the surface, Canadian high pressure will nose its way into the Ohio Valley behind an exiting cold front at the start out the extended. But low pressure developing over the Great Plains will pull the aforementioned warm frontal boundary northward through the Commonwealth Wednesday. Temperatures should warm significantly in return southerly flow as H850 temperatures climb to around 17 or 18 C. A surface cold front will attempt to drop southward closer to the Ohio River by late Saturday but will meet fierce resistance from high pressure to the south leaving our area within the warm sector but with heights dropping enough that there could be a bit better chance for some rain. Sensible weather features a few lingering showers across the area to start out the extended portion of the forecast. A cold front will be pushing off to the east. But any lingering shower or thunderstorms activity will be ending through the day as high pressure begins to build into the region. A warm frontal boundary is expected to lift north across the area by Wednesday. At this time it appears strengthening high pressure aloft will likely limit the threat of rain to just isolated activity. Generally dry conditions will prevail thereafter until possibly late Friday, or more likely Saturday as a cold front drops southward towards the Ohio River. Isolated to widely scattered showers and thunderstorms will be possibly to wrap up the extended. Daily high temperatures will warm from around 80 at the start of the period, well into the 80s during the latter half of the week. A few locations will even flirt with the 90 degree mark. Overnight lows will respond similarly, going from a pleasantly cool 50s to the mid 60s for the latter portions of the forecast window. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) ISSUED AT 840 PM EDT SAT MAY 18 2019 VFR conditions will prevail through the forecast period as high pressure over the southeastern U.S. continues to control our local weather. Any lingering showers or storms currently out there will dissipate quickly this evening with loss of daytime heating. Some river valley fog is expected again tonight, but the TAF sites should not be affected - except perhaps SME due to the earlier rain. As low level winds increase late tonight in the southwest part of the area, LLWS is expected to develop for SME and have included. Daytime mixing on Sunday will result in gusty southwest winds, mainly in the western and northern part of the forecast area, where some gusts of 20 to 25 knots can be expected. A dying cold front may bring some showers or a thunderstorm to western parts of the area late in the period. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...GREIF SHORT TERM...SBH LONG TERM...RAY AVIATION...SBH/GREIF
Area Forecast Discussion
National Weather Service Key West FL
919 PM EDT Sat May 18 2019 .DISCUSSION...In the middle and upper levels(700-200 mb), latest available satellite imagery overland with model streamline analysis as of 900 pm depicts the center of a cold core, near 550 dm at 500 mb cyclone positioned of NE Wyoming with an attendant negatively tilted trough axis that extends southeast to the piney woods of NE Texas. Downstream of that, middle and upper ridging build rather sharply at the convergence of this trough (where associated severe weather is in progress), northwards towards Lake Superior and including the entire Midwestern, Mid-Southern and Entire Eastern United States, with the exception of east northeast to west southwest oriented 500 mb trough axis centered at about 28N 77W but continuing to extend across the mid-Florida Peninsula. Nevertheless, water vapor imagery is detecting lots of dry air moving across the Florida Peninsula, Florida Keys and all surrounding waters. At the surface and in the lower to middle levels(Surface to 700 mb), latest available land and marine surface observations and analysis as of 900 pm detail a near 1020 mb surface ridge situated from the West Central Atlantic westwards to across Northern Florida. The 00Z evening sounding illustrated a mostly gentle east flow off the surface to about 825 mb where it becomes west above that increasing appreciably in magnitude above about 500 mb. PWAT was up about 12 hundreths of an inch from 24 hours prior. Nevertheless it remained rather unstable with 7 degree c/km lapse rate from about 800 to 630 mb. .CURRENTLY...As of 900 pm, skies are partly cloudy across the islands and surrounding waters, but are mostly cloudy attm across the outer Florida Straits where Cuban boundaries have been colliding over the very warm waters where radar detects scattered showers and isolated storms. Temperatures across the islands have only fallen into the lower 80s with dewpoints in the lower to mid 70s. C-man stations along the Florida Reef are still east or east southeast at 10 to 15 knots, but islands stations are closer to 10 mph or less. Though convection once again developed over SW FL Mainland it dies rapidly as soon as it exited the Peninsula into the Florida Bay and Nearshore Gulf waters. Abundant drier air in the mid- levels may have been responsible for its quick demise. .SHORT TERM...Overnight, the 500 mb trough that is now over Florida will start to move slightly eastwards but may still contribute a bit to the overall instability across the South Florida Mainland. That being said the latest available forecast soundings maintain PWAT between 1.25 and 1.50 inches overnight and during Sunday. Latest HRRR and WRF suggest a few showers and storms could move across the islands from leftover boundaries very late tonight. Given the presence of boundaries north of south of the Keys, will maintain the inherited slight chance, 20%, for showers and storms overnight. && .MARINE...Gentle breezes expected overnight and Sunday. && .AVIATION...VFR conditions will prevail overnight and Sunday at the EYW and MTH island terminals. Isolated to widely scattered showers may develop within moderate easterly flow later tonight into early Sunday morning, but confidence in any impact on the terminals is too low to mention in the TAFs at this time. A cloud line may develop along the Keys island chain during the day on Sunday, but again confidence in any impact is too low to mention in the TAFs. Surface winds will remain from the east around 10 knots through the period. && .KEY WATCHES/WARNINGS/ADVISORIES... FL...None. GM...None. && $$ Public/Marine/Fire...Futterman Aviation/Nowcasts....Jacobson Upper Air/Data Collection......SD Visit us on the web at Follow us on Facebook and Twitter at:
Area Forecast Discussion
National Weather Service Lake Charles LA
1030 PM CDT Sat May 18 2019 .UPDATE... Updated hazard grids and forecast for southeast Texas to add Tornado Watch number 190 issued by SPC until 4 am local that will include Hardin, Tyler, Jasper, and Newton Counties. Rua && .PREV DISCUSSION... /issued 917 PM CDT Sat May 18 2019/ UPDATE... Latest water vapor imagery shows a mid level short wave from Oklahoma down into Central Texas moving to the east. This short wave will be moving into a very moist air mass as 30-40 knot low level jet pumping in Gulf moisture with PWAT up to near 1.75 inches on the 19/00Z KLCH upper air sounding. There has been a bit of a cap in place, and the latest sounding still has a notion of this at 70H or 10K feet. However, lift from the short wave should be able to get at-least some shower activity going and area radars are showing an increase in the shower activity over Southeast Texas during the past half hour or so. Clusters of strong to severe storms are noted mainly northwest of the forecast area, and that is the question for the overnight as to if this activity will congeal into a linear mcs and how far south the strong activity will get. Latest runs of the HRRR and consensus of other short term guidance, does show activity to the northwest and west coming together in a linear fashion before midnight, then strongest activity moving into and across the northern zones during the overnight, with best pops and risk of any strong thunderstorms mainly in upper Southeast Texas, and staying mainly north of the highway 190 corridor as it moves into Louisiana. Therefore, will reflect this in the first period for the forecast, with best rain chance, rainfall amounts, and mention of strong to severe over the northern zones. The main risk hazards for the storms will be straight-line winds and cloud to ground lightning. Otherwise, remainder of the forecast is on track. Rua PREV DISCUSSION... /issued 658 PM CDT Sat May 18 2019/ DISCUSSION... 00Z TAFS AVIATION... Scattered showers will continue to move from south to north across the area this evening in advance of a line of strong to severe thunderstorms that is expected to move into the area late tonight into Sunday morning. The most likely time of impact at each of the terminals is highlighted in their respective TEMPO groups. Visibility reducing heavy rainfall and locally strong winds will accompany this line storms as they move through the terminals. MVFR ceilings will prevail through the night at BPT and LCH with VFR ceilings lowering to MVFR at AEX, LFT and ARA later this evening. Southerly winds will relax somewhat overnight, but gusts up to 20 knots will remain possible. Behind the line of storms, scattered showers will continue through the morning at BPT, LCH and AEX and through early afternoon at LFT and ARA. However, ceilings are expected to lift to VFR. Winds will moderate through the afternoon as the pressure gradient begins to relax. Jones PREV DISCUSSION... /issued 315 PM CDT Sat May 18 2019/ DISCUSSION... Strong onshore flow is noted today, with southerly winds gusting in the 20 to 30 mph range. Winds should relax over land after sunset this evening. Not much activity so far on the radar, just a few showers noted across southeast Texas and parts of southwest and central Louisiana. This activity should increase later tonight. Per SPC, there is a chance for strong to severe storms in the southeast Texas and parts of central and southwest Louisiana, where damaging winds, large hail, and isolated tornadoes are all possible. With these nighttime events, everyone should think of ways to receive weather warnings while they are asleep. Thanks to an upper level disturbance, Sunday morning will continue scattered to numerous showers and thunderstorms across the entire region, before tapering off as we go through the afternoon into the evening. SPC has only a marginal or 5 percent chance for strong to severe storms on Sunday. Monday will be dry, and there will be a small chance for showers and thunderstorms on Tuesday as another upper level disturbance moves north of our region. The remainder of the week looks dry until Friday when another upper level system gives us a small chance for storms. Temperature-wise, we look to be near normal for the entire forecast period for high temperatures, while we run 5 degrees above normal for low temperatures thanks to the persistent southerly flow. MARINE... South to southeast winds of 15 to 20 knots will continue through the overnight hours, so have a small craft advisory in place. Will need to re-evaluate later tonight to see if winds relax after sunrise as we currently have in the forecast. Tides are running a little over a foot above normal. Not enough for a coastal flood advisory, but this will also be monitored as we approach high tide tonight. && .PRELIMINARY POINT TEMPS/POPS... AEX 72 86 72 88 / 80 80 10 20 LCH 75 84 74 86 / 50 20 10 10 LFT 75 86 74 89 / 40 80 10 10 BPT 74 85 74 85 / 50 20 10 10 && .LCH WATCHES/WARNINGS/ADVISORIES... LA...None. TX...None. GM...Small Craft Advisory until 7 AM CDT Sunday for GMZ450-452-455- 470-472-475. Small Craft Exercise Caution until 7 AM CDT Sunday for GMZ430- 432-435. && $$ PUBLIC...07
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
708 PM CDT Sat May 18 2019 .SHORT TERM...(This evening through Sunday night) Issued at 255 PM CDT Sat May 18 2019 An area of weakening surface low pressure was located in southwest Minnesota, and a warm front was laid out west to east along I-90 today. Temperatures were in the upper 70s and 80s south of the front. Meanwhile north of the front temperatures were in the upper 40s to lower 50s with brisk east winds, low clouds, and periods of drizzle or rain showers. Instability has built south of this frontal boundary, so showers and thunderstorms are expected to develop and lift northward into southeast Minnesota and western Wisconsin later this afternoon and evening as a shortwave trough moves up from the south. There could be some strong to severe storms as highlighted by the SPC slight risk. Given the mid-level lapse rates, large hail looks to be the primary concern. However could have some strong wind as the storms advect northward, so that is the secondary concern. Meanwhile the threat for tornadoes is very low. Overall this is not a significant severe weather set up, but people should still seek shelter indoor away from windows if a severe thunderstorm warning is issued. Overnight the aforementioned upper level shortwave trough will lead to pretty impressive cyclogenesis, so that Sunday morning we should have a 993mb surface low across southwest Wisconsin. The atmospheric response to this will be strengthening winds and cold air advection over Minnesota and Wisconsin. For that reason increased winds on Sunday, and kept high temperatures near the record cool maximum for mid-May. Thermal profiles seem warm enough for pretty much all rain at most locations, but could have a few flakes mixed in across the north. No accumulation is expected. .LONG TERM...(Monday through Saturday) Issued at 300 PM CDT Sat May 18 2019 The extended period (Monday-Saturday) will be highly controlled by the strength of the upper level ridge building across the southeastern CONUS. This upper ridge will be key on frontal positions late in the week, and more humidity building across the Upper Midwest. As with previous discussions, the upper ridge building across the southeast will lead to an increase in temperatures, and humidity levels by mid/late week. This will set the stage for an increasing chance of precipitation by Tuesday afternoon, and Tuesday night. Beyond Tuesday, the timing of the next chance of widespread precipitation is uncertain, but confidence remains high that another system will bring widespread precipitation over the Upper Midwest sometime mid/late week. In the short term, or through Tuesday morning, high pressure will control the weather with dry and slightly cool than normal conditions. However, it will be short-lived as the next strong short wave moves across the Rockies, and into the Plains by Tuesday afternoon. Initially, this system doesn`t support enough instability to generate widespread thunderstorms. However, heavy rainfall is still very likely. The layer integrated water vapor moisture transport value by Tuesday afternoon are extreme, or nearly 4-6 standard deviations above normal for this time of year. Thus, once the initial bands of precipitation develop, rainfall rates will be very efficient and lead to even more problems with areal flooding. This is especially concerning as ground moisture is abnormally wet, and any additional heavy rainfall will lead to more river flooding. I wouldn`t be surprised to see flood watches issued by the middle of the week based on these conditions expected. This area of precipitation Tuesday night will likely move northward with a brief period of dry weather Wednesday. However, confidence remains low on any 24 hour period remaining dry based on the speed of the short waves moving out of the Rockies this week. One other item to note past Tuesday is the increasing instability and how will that play in the weather forecast late in the week. The upper jet is expected to be abnormally strong for the Upper Midwest this week. Due to the fact that these short waves ejecting out into the Plains will develop surface lows, the overall increase in wind shear values is higher, and thus the higher probability of severe weather. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 708 PM CDT Sat May 18 2019 Widespread MVFR ceilings across the area will gradually lower this evening, and by late tonight, should be IFR most everywhere as rain envelops the area. Some thunderstorms are possible this evening at KEAU as current activity in southeast MN spreads northeast. A strengthening low pressure system to the south and southeast will result in ene winds generally 15-25 kts, with winds turning northerly as the low moves east. Improvement in clou cover will not take place until late afternoon Sunday in western MN and later Sunday evening in Wisconsin. KMSP... The HRRR has had a decent handle on the timing of showers moving into KMSP, with showers likely arriving after 04Z. There is a small chance of thunder around 04Z for an hour or so, but this seems doubtful with best instability remaining southeast of KMSP. However, IFR ceilings are very much expected late tonight and continuing through midday Sunday, along with a northeast wind gusting around 25 knots, and confidence in this is above average. Improvement is not expected until late Sunday afternoon or evening. /OUTLOOK FOR KMSP/ Mon...VFR. Wind NE 5 kts. Tue...VFR. MVFR and IFR/-SHRA likely late. Wind E at 15G25 kts. Wed...MVFR/IFR/-SHRA early, then VFR. Wind SE at 10G20 kts && .MPX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. && $$ SHORT TERM...JRB LONG TERM...JLT AVIATION...TDK
Area Forecast Discussion
National Weather Service Marquette MI
747 PM EDT Sat May 18 2019 .SHORT TERM...(This evening through Sunday) Issued at 412 PM EDT SAT MAY 18 2019 WV imagery and RAP analysis indicated mid/upper level ridging from the se CONUS through the upper Mississippi Valley between a trough over the Rockies and a low over northern Ontario. At the surface, light easterly winds prevailed through Upper Michigan between the ridge over northern Ontario and the low pressure system over the central Plains. Moderate to occasionally heavy rain has spread across the northern tier counties today while the south central counties have generally experienced only light isolated showers. The rain was supported by 800-600 mb fgen and associated 300k-310k isentropic lift. A more prominent shortwave trough over the southern Plains has combined with stronger moisture inflow and instability to support stronger convection/t-storms over the southern/central Plains into the mid-Mississippi Valley today. Tonight, model guidance consistent with dissipating area of rain across northern MN into northern WI and the nw half of Upper Mi as supporting 800-600 fgen forcing weakens across the area. As a result, expect a general break in the steady rain from this evening into the early overnight hours. The break in the rain, however, may allow upslope enhanced advection fog to move in from Lake Superior in ne flow. Northeast-facing higher terrain may even experience patchy dense fog at times through much of tonight. As the stronger shortwave begins to lift north later tonight from the southern/central Plains increasing upper diffluence and deep layer q-vector convergence associated with he approaching storm system will allow widespread rain to again spread into south central Upper Mi late tonight and across the rest of the U.P. on Sunday. Fortunately due to movement of the mid-level and sfc low, best forcing and deepest moisture with the system should lift from southern tier counties late tonight/early Sunday into northern tier counties by midday, allowing the heavy rain potential to shift from south to north from late tonight into Sunday. Hopefully, this will help alleviate any potential flood concerns with system despite favorable deep warm moisture profile and very high PWATs of 1-1.5 inches. Even so, ground is still pretty wet, so will keep the ESF statement to highlight rises in river/streams and the potential for minor flooding/ponding of water in low-lying or poor drainage urban areas. Another potential forecast concern with system, is that the NAM is still showing enough CAA/dynamic cooling behind the strengthening system to show ptype changing from rain to snow Sun afternoon over far western counties. Would not be surprised to see some minor accumulation over the higher terrain areas, but have a hard time envisioning any significant accumulation of several inches per KIWD NAM sounding given that pcpn will be occurring during a late May afternoon. Finally, also expect fairly gusty ne winds during the day on Sunday as gradient really tightens up on backside on strengthening storm system. Mixing/momentum transport should support wind gusts of 30-35 mph and perhaps as high as 40 mph in some spots. .LONG TERM...(Sunday night through Saturday) Issued at 310 PM EDT SAT MAY 18 2019 Wet weather will be winding down through the overnight hours Sunday into Monday as a nearly vertically stacked low pressure system begins to pull out of the region. At 00Z Monday most models indicate sfc low pressure located over northern Lake Michigan with 500mb height minimums over the central/western UP or northern WI. Strong northeasterly flow will bring an onshore/upslope component that is expected to increase QPF over higher terrain, where perhaps as much as 0.4-0.6" of additional rainfall would be expected Sunday night. Elsewhere, a widespread 0.2-0.4" is forecast, with lower amounts along the WI border. There remains a chance for some snowflakes to mix in over portions of the southwestern Upper Peninsula (especially Gogebic County) as low temperatures drop to near 35, but little to no accumulation is expected. The NAM and to some degree the CMC are the only models still latching onto any snow reaching the surface and they have both begun to back off on this solution. High pressure will build in behind this system and dry conditions will prevail midday Monday through Tuesday evening. After highs generally in the 50s Monday, most locations should warm into the low to mid 60s Tuesday. Expecting mixing to allow for dry RH values in the afternoon falling to near 25 percent. A very broad closed upper low will settle in and spin over the western CONUS through the middle of next week, with a series of shortwaves expected to affect our region Tuesday night through Thursday night. Areas of off and on showers through this period are likely, but at this time, thankfully, prolonged heavy rain should not be of too much concern PWATs don`t get much above 1 inch and precipitation is expected to be relatively progressive. As sfc flow veers to the south and southwest on Thursday, warmer air will filter into the region with widespread upper 60s to mid 70s temperatures expected during the day. The first potential for widespread thunderstorms this spring could come Thursday into Friday as the aforementioned upper low opens up and propagates northeastward through the area. Stay tuned for details on the evolution of this system. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 747 PM EDT SAT MAY 18 2019 In the wake of one organized area of rain, abundant low-level moisture will linger. As a result, at KIWD, expect generally IFR cigs with ocnl LIFR this evening. At KCMX, there may be enough drying during the night to allow initial LIFR cigs to improve to IFR late evening then to MVFR overnight. At KSAW, upslope ne winds will likely maintain LIFR cigs with the potential for fog to drop vis blo airfield landing mins. Later tonight and thru Sun, approaching low pres from the sw will spread mdt to at times hvy rainfall into Upper MI. Expect conditions to fall to prevailing LIFR at KIWD and IFR at KCMX. LIFR will continue at KSAW. In addition, ne winds will become gusty to around 30kt at all terminals. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 412 PM EDT SAT MAY 18 2019 As low pressure approaches from the central Plains tonight into Sunday, northeast winds will gradually increase up to 30 knots on western Lake Superior late this afternoon into tonight. Expect the tightening gradient to bring northeast gales of 35-40 knots over the west end of Lake Superior early Sunday morning that may expand into the east Sunday afternoon. A gale warning was issued over western Lake Superior. Northerly 30 knot winds Sun night will gradually diminish Monday as the low moves out of the region. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... Gale Warning from 5 AM EDT /4 AM CDT/ to 7 PM EDT /6 PM CDT/ Sunday for LSZ162-263. Lake Michigan... None. && $$ SHORT TERM...Voss LONG TERM...KCW AVIATION...Rolfson MARINE...Voss
Area Forecast Discussion
National Weather Service San Francisco Bay Area
855 PM PDT Sat May 18 2019 .SYNOPSIS...Showers will taper off from west to east this evening and mostly end late tonight. Widespread showers and isolated thunderstorms are then likely on Sunday, mainly in the morning, as the core of the cold upper low passes over the region. Dry weather returns late Sunday night through Monday. A cold system dropping in from the north will bring renewed shower chances Monday night and Tuesday. Drier weather is forecast for later next week, but temperatures will remain cooler than normal. && .DISCUSSION...As of 8:55 PM PDT Saturday...An impressive late season storm system brought widespread light to moderate rainfall to our region today. Rain totals thus far have ranged from less than a quarter inch in some of the sheltered inland valleys to more than 2 inches in isolated higher elevation locations in Sonoma and Marin Counties. Current radar shows that scattered shower activity continues across our region. Latest satellite and short-term model output indicate that shower activity will end from west to east overnight after cold frontal passage. But there will be only a short break in precipitation as the cold core associated with an upper low approaches by Sunday morning. Latest HRRR shows a line of showers sweeping across our area from about sunrise through mid morning, with scattered showers then continuing behind that line into the afternoon hours. With the cold core of the upper low forecast to track directly across the SF Bay Area tomorrow, isolated thunderstorms will also be possible. Based on the latest NAM, thunderstorm chances will be highest in our area during the morning hours when CAPE values are forecast to peak. Thunderstorm potential will then mostly shift eastward into the Central Valley by afternoon, but with some sunny breaks and strong afternoon surface heating from the late May sun, we could see isolated thunderstorms persisting into the afternoon hours. Shower activity is forecast to taper off during the late afternoon and early evening hours and mostly end by late evening as the upper low moves off quickly to our southeast. Additional rainfall totals from this evening through late Sunday are forecast to be mostly in the range of 0.25-0.75". Dry and cool conditions are forecast for Sunday night and Monday before the next system sweeps in from the northwest, bringing renewed shower chances from Monday night through Tuesday evening. This system is expected to contain much less moisture compared to the only currently impacting our area. Therefore, rain totals on Monday night and Tuesday are expected to be on the order of a quarter inch or less. For the remainder of the work week, an upper low is forecast to remain anchored over the Great Basin. Disturbances rotating around this low may bring showers into our area at times, but chances are generally low that measurable rain will occur. Rain chances will be highest across the northern and eastern portions of our area. Rain chances then increase over the Memorial Day weekend when the upper trough position is forecast to retrograde from the Great Basin to over California. It should be noted that it currently does not appear that the weekend will be a washout, but instead partly cloudy with a chance of showers. Temperatures will remain well below normal through Tuesday. Some warming is expected later next week, but temperatures will remain cooler than seasonal averages. && of 5:15 PM PDT Saturday...MVFR cigs through Sunday. Rain will be tapering off after 02-03Z as the main frontal band moves through and we go into the showery regime. Models indicate an increase in shower activity between 12Z and 18Z as the upper low moves inland over northern California. There will still be a threat for showers and even a thunderstorm Sunday afternoon due to an unstable airmass behind the low. Winds will be steady 10-15 kt but will be gusty through early evening...could see occasional gusts over 25 kt. LLWS possible this evening as winds at 925mb are strong out of the south. Vicinity of KSFO...Rain expected to decrease after 02-03Z. Cloud bases expected to lower to 1500-2000 feet as rain has saturated the lower levels of the atmosphere. Cigs should rise after 06Z then lower after 12Z as shower activity picks up again. Shower activity will decrease Sunday afternoon but cannot rule out the possibility of an isolated thunderstorm. Gusty winds to 25 kt through 03Z with possible LLWS otherwise southeast winds 10-15 kt. SFO Bridge Approach...Similar to KSFO. Monterey Bay Terminals...Generally MVFR cigs. Rain decreasing after 03-04Z but a round of showers is expected after 13-14Z continuing through 18Z. Winds should stay below 15 kt at the surface but LLWS is possible through tonight. && .MARINE...As of 8:32 PM PDT Saturday...A low pressure system will move into the northern California waters early Sunday. This will bring a slight chance of thunderstorms to the coastal waters tonight and Sunday. Moderate southerly winds will gradually shift to the west Sunday then northwest Sunday night. Swells will be building overnight creating hazardous conditions particularly for smaller vessels. && .MTR WATCHES/WARNINGS/ADVISORIES... .Tngt...SCA...Pt Arena to Pt Reyes 0-10 nm SCA...Pt Reyes to Pigeon Pt 0-10 nm SCA...Pigeon Pt to Pt Pinos 0-10 nm SCA...Pt Pinos to Pt Piedras Blancas 0-10 nm SCA...Pt Arena to Pigeon Pt 10-60 nm SCA...Pigeon Pt to Pt Piedras Blancas 10-60 nm SCA...Mry Bay from 9 PM until 3 AM SCA...SF Bay until 3 AM && $$ PUBLIC FORECAST: Dykema AVIATION: W Pi MARINE: W Pi Visit us at Follow us on Facebook, Twitter, and YouTube at:
Area Forecast Discussion
National Weather Service Paducah KY
1047 PM CDT Sat May 18 2019 .UPDATE... Issued at 1044 PM CDT Sat May 18 2019 Update for 06z aviation only. && .SHORT TERM...(Tonight through Monday night) Issued at 255 PM CDT Sat May 18 2019 Lake Wind Advisory working out well as breezy south winds continue. We will let it expire at 6 p.m. No plans on adding a headline at this time for Sunday. However, we will easily achieve Lake Wind Advisory again. Will let later shifts determine if we will get close to a traditional Wind Advisory or not. Either the evening or mid shift can run with the next headline. Large area of convection to our west from east KS into east OK and ncntrl TX. The 12z HRRR was decent in its 6 hour depiction. Will use it as a guide for our weather into tonight. Expect increasing clouds, with some convection reaching the Ozark Foothills by 00z or so. Not sure how the convection will unfold as it moves east across SEMO through the evening. Cannot rule out a strong storm. There may be an uptick as the wind fields get stronger toward midnight and beyond, up to about the MS River. All in all, confidence is quite low in terms of severe. Best PoPs however will be west of a Evansville IN to Murray KY line. Could be some locally heavy rain late tonight into Sunday over SEMO. Even more uncertain is the chance of severe on Sunday. Upper level trof to our NW will be over MO into IA at 12z. It will move northeast toward the Great Lakes through the day. Best shear parameters will be in the morning, when ongoing convection will likely be on the decrease as best forcing moves away. Models show instability developing ahead of an approaching front heading into the afternoon. Two factors will be going against robust strong to severe. Diminishing shear parameters, along with H5 temps -8 to -10C yielding spatially narrow CAPE (seen in forecast soundings) as Lapse rates run from about 4.8 to 5.5 (not favorable). Also, moisture will be in question. Best moisture will be east from the EVV Tri-state into west KY and the KY Pennyrile. Thus our best chance of a strong to severe storm is in this area. Main hazard should be locally strong winds. Hail threat seems minimal. Sfc/Boundary layer flow veers ahead of the front. So any tornadic element should be minimal (short lived, brief) if it can even happen at all. The front will push east Sunday night, around midnight or shortly after, bringing an end to the convection from southwest IN into west KY. Monday through Monday night as high pressure builds in behind the front, dry weather is forecast, along with a dip in temp/humidity levels. The very warm and humid air will not make it too far south of the area. .LONG TERM...(Tuesday through Saturday) Issued at 255 PM CDT Sat May 18 2019 The amplified, western trof/eastern ridge mid level pattern will continue across the CONUS in the extended forecast period, with periodic shortwaves ejecting from the persistent and large trof in the west. This energy, including jet streak energy aloft, is forecast to stay to the west and north of the PAH forecast area much of the time. The only exception to this would be late Tue when the medium range models show a stacked low will dig its way into the northern Plains, swinging a surface warm front through our region, possibly touching off a few showers and tstms during the daylight hours, and providing a robust southerly breeze. This will be followed into the evening by larger scale lift associated with height falls and jet streak energy to the east-southeast of the parent low. Showers and tstms are forecast to become more common Tue evening and overnight. Wind fields aloft suggest the possibility of some tstms becoming severe, mainly in the evening, with damaging winds and localized heavy rain the primary hazards. By Wed, the southeastern CONUS ridge, which our region will be on the periphery of, is progged to begin to quickly recover. Model consensus suggests a surface cold front will not make it into our region, thus warm and humid (summerlike) conditions will continue for us. The anticyclonic flow aloft should limit updraft strength and coverage of tstms across our region Wed. Wed night and beyond, afternoon and evening deep moist convection is expected to be sparse under the ridge (areas north of I-64 would have a little higher chance of isolated convection). However, toward the weekend, additional mid level shortwave energy impinging on the ridge may generate MCS activity which may make it into the PAH forecast area as early as Fri, but this should be a little more probable by Sat. && .AVIATION... Issued at 1044 PM CDT Sat May 18 2019 We will have run move across the area overnight and through at least Sunday morning. At times we may even encounter a clap of thunder. Cigs and Vsby will go MVFR at times overnight and in the morning. Where we lose the gusts...mainly EVV and OWB we could encounter LLWS. VFR condition start to return late Monday. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...None. MO...None. IN...None. KY...None. && $$ UPDATE...KH SHORT TERM...08 LONG TERM...DB AVIATION...KH
Area Forecast Discussion
National Weather Service Pendleton OR
858 PM PDT Sat May 18 2019 .UPDATE... Latest radar imagery showed an area of showers generally between (now mainly north of the Dalles) and Hermiston. This area of showers had some embedded thunder in it earlier, though the thunder apparently has ended. This area of showers is moving to the north. High resolution guidance handling of this area has been mixed. The RAP earlier did not have this feature at all, though now has seemingly caught on to it. The HRRR has done a much better job. The global models` performance has also generally been poor. Both the HRRR and RAP continue to bring this feature northward over the next few hours into southern Washington, before eventually weakening it. Therefore, have increased pops over this area. Also, at least for the next few area, have kept a mention of thunder. Otherwise, made some adjustments to cloud cover, temps and wind. && .PREV DISCUSSION... /issued 427 PM PDT Sat May 18 2019/ AVIATION... 00Z TAFS...Slowly deteriorating weather conditions are expected for DLS, PDT, RDM and BDN this evening into Sunday as an area of low pressure off the coast moves into northern California. Periods of rain will develop and widespread MVFR CIGS are expected at these locations. At RDM and BDN, MVFR VSBYS are also psbl and some localized IFR Can not be ruled out Sunday. Elsewhere, generally VFR conditions are expected. Gusty NW winds 20 to 25 kts are expected Sunday aftn. PREV DISCUSSION... /issued 155 PM PDT Sat May 18 2019/ SHORT TERM...Tonight through Tuesday...It will be cool and wet during the short term. A closed low currently centered near 41N/133W is rotating precipitation across southwest Oregon this afternoon, and precipitation will increase from the south overnight. The first band of showers will bring relatively light amounts of precipitation tonight, but the next band of precipitation right at the heels of the first one will bring another round of moderate to heavy rain. The front on Sunday and Sunday night will be stationary in a NW-SE line from The Dalles to Burns, and 24-hour QPF of 0.5-1.5 inch is forecast over northeast Oregon. The heaviest accumulations will be over the southern Blues and the Ochoco-John Day Highlands. Some areas are already saturated from Thursday`s rain event, prompting the issuance of a Flood Watch. Although flooding is not expected to be widespread, the purpose of the watch is to alert those of the possibility of rock or mud slides in steep terrain and localized flooding. Most of south central and southeast Washington as well as central and north central Oregon will have light to moderate rain Sunday and Sunday night but less QPF--up to a 0.25 inch for most locations. Will keep the slight chance of thunderstorms for the far northern Blues east to Idaho Sunday afternoon, although clouds could become overcast and limit instability. The closed low will travel southeast across the California and the Desert SW Sunday night and Monday morning. Showers on Monday will mostly be scattered, but another closed low approaching the Oregon coast will bring numerous showers Monday night and Tuesday. Heaviest accumulations will be over the Blues and Wallowas and the east slopes of the WA/OR Cascades where 0.25-0.5 inch is forecast. Other areas will likely receive less than a 0.25 inch of rain. Light snow accumulations are possible above 5000 feet on Tuesday. Wister LONG TERM...Tuesday night through Saturday...Models in good agreement in the short-term with two lows pinwheeling around one another over the Northern High Plains through Thursday. This will result in general north to northeast upper level flow over the Pacific Northwest. There are minor differences spatially and temporally with the lows, but overall scattered showers, mainly during the afternoon and early evening, will continue, primarily over the Oregon mountains. By Friday the models begin to diverge. The GFS shows a disturbance moving down from BC while the ECMWF shows the western most low retrograding over Oregon. Either solution results in an increasing chance of showers Friday over the CWA, mainly over the mountains. By Saturday, the GFS shows a strengthening upper low moving from BC to southern Washington while ECMWF shows a more open trough. Given the discrepancies between the two solutions, will continue a mention of afternoon and evening showers, mainly over the mountains. In summary, the active weather pattern will continue over the Pacific Northwest. Daytime highs will remain near to slightly below normal through the period. Earle && .PRELIMINARY POINT TEMPS/POPS... PDT 50 60 47 66 / 40 70 60 20 ALW 51 67 48 68 / 10 60 60 20 PSC 55 73 51 73 / 20 30 30 10 YKM 52 70 51 68 / 80 70 30 30 HRI 52 66 49 71 / 60 60 50 20 ELN 48 68 47 63 / 70 60 30 40 RDM 40 59 39 60 / 20 50 50 30 LGD 44 58 43 60 / 20 90 90 30 GCD 43 51 42 58 / 30 90 80 40 DLS 51 63 50 64 / 60 80 60 30 && .PDT WATCHES/WARNINGS/ADVISORIES... OR...Flood Watch from 8 AM PDT Sunday through Monday morning for ORZ044-049-050-502-503-505>508. WA...None. && $$ 77/91/77