Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/08/19

Area Forecast Discussion
National Weather Service Bismarck ND
816 PM CDT Sun Apr 7 2019 .UPDATE... Issued at 814 PM CDT Sun Apr 7 2019 Current radar observations show scattered showers across northeast Montana, heading for northwest North Dakota this evening. Increased the probability of precipitation northwest for the next few hours as these showers move into the area. The latest observations were also blended in for good measure. UPDATE Issued at 517 PM CDT Sun Apr 7 2019 Mild temperatures continue this evening. In fact, Bismarck managed to hit 71 degrees just before 5 PM CDT today, and is still sitting at 70 degrees. Current satellite observations show scattered high clouds moving into western and central North Dakota from the west. Expect increasing cloud cover tonight and diminishing winds, with scattered showers developing as a jet streak moves through the area. The latest observations were blended in for this forecast update. No other changes were needed as the current forecast remains on track. && .SHORT TERM...(This evening through Monday) Issued at 302 PM CDT Sun Apr 7 2019 Mostly clear skies and warm temperatures across western and central North Dakota this afternoon under weak ridging aloft. Westerly winds gusting to 35 mph, temperatures well into the 60s, and RH below 25 percent have created some elevated fire weather concerns. Tonight, a mid to upper level jet streak will bring increasing clouds and scattered rain showers across much of the area. Overnight lows should remain well above freezing. Cyclonic flow aloft and steep low-level lapse rates may lead to isolated showers developing mainly east of the Missouri River Monday afternoon. The HRRR has been consistent in this occurring, but model soundings look rather dry. Will leave out of the forecast for now. Expect slightly cooler temperatures and another breezy day for Monday. .LONG TERM...(Monday night through Sunday) Issued at 302 PM CDT Sun Apr 7 2019 The main concern for the extended forecast is the track of a strong low pressure system across the Central Plains late Tuesday through Thursday. An upper-level trough is forecast to move into the Pacific Northwest on Tuesday, tracking east-southeastward and deepening into a closed low over the Central Plains by Thursday. Broad lee cyclogenesis is forecast to occur late Tuesday over northeast Colorado. Meanwhile, models try to develop the associated 700 mb low over Montana/Wyoming late Tuesday, migrating towards Nebraska on Wednesday. Initial forcing for ascent from mid-level frontogenesis and isentropic lift should generate precipitation from east central Montana to north central South Dakota Tuesday afternoon. Boundary layer temperatures should remain warm enough for rain across southwest North Dakota through Tuesday evening before a mix or change over to snow during the overnight hours as precipitation spreads eastward. With cooler lower to mid-level air being advected in from the north and surface wet bulb temperatures dropping below freezing, expect precipitation to fall as mostly snow or a rain/snow mix on Wednesday as the system moves into the Central Plains. So how much of North Dakota will impacted beyond Tuesday night? Deterministic model guidance has indicated a slight southward shift in the storm track over the last 24 to 36 hours. Despite a couple runs with a more northern track, the ECMWF has been much more consistent with its more southern storm track over the last few days. The GFS continues to bounce around, but its 12Z run is now more closely aligned with the ECMWF. The NAM is a bit farther north, and is known to have north bias with Colorado lows when a cool, dry air mass is entrenched across the northern Red River Valley (as appears to be the case here). GEFS plumes continue to show considerable spread, even at Mobridge and Aberdeen which have always been more likely to see higher QPF. Several members produce less than 0.1" QPF at these two locations. Meanwhile, the majority of members at Bismarck show below 0.2" QPF with a few higher outliers. This seems to imply that a southward shift in storm track may be slightly more likely than a northern shift. As of this writing, the best chances for accumulating snow lie across the South Dakota border. A northward shift could bring accumulating snow as far north as Interstate 94, while a southern shift may leave the state completely snow-free. Regardless of where precipitation falls, below normal temperatures are favored across the entire area mid to late week. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 625 PM CDT Sun Apr 7 2019 High clouds will continue to increase across western and central North Dakota this evening and tonight. Gusty winds early this evening will rapidly diminish by late evening. Scattered rainshowers are forecast to across western North Dakota later this evening, moving eastward through central North Dakota tonight. Skies look to clear out tomorrow morning, giving way to mostly sunny skies during the afternoon with gusty winds developing again. Overall, expect VFR flight conditions at all terminals through 00z Monday evening. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...TK SHORT TERM...Hollan LONG TERM...Hollan AVIATION...TK
Area Forecast Discussion
National Weather Service Birmingham AL
1002 PM CDT Sun Apr 7 2019 .UPDATE... Evening Update. && .SHORT TERM... Boundary interaction, convergence axis and overall instability have diminished this evening. Therefore, the overall thunderstorm trend has also seen a big decrease in coverage and intensity. Have removed the western areas from a Marginal Risk overnight. Showers and thunderstorms remain possible overnight, but if any produce winds or hail, it will remain below severe limits. Made some changes to the pops overnight. All eyes have shifted to the upper low and large convective boundary to our west. This boundary will continue eastward and enter Central Alabama later tonight. Have the highest pops aligned more north/south than previous and best chances west. The various HI-Res models and current global runs have several differing solutions on the overall upper flow over the area. There also remains the issue of boundary locations and what/when initiates the thunderstorms on Monday. The atmosphere appears to have plenty of moisture, the upper low moves closer and influences the large scale lift, meso- scale boundary are in place, bulk shear is higher than the previous few days especially in the afternoon. At any rate, tomorrow will certainly be tricky for timing and placement. But it still appears that storms will fire up and have severe potential. 75 Previous short-term discussion: --Marginal Risk of severe storms through midnight-- Late this afternoon, the northwest counties were located along a moisture gradient. Low precipitable water values resided south and east over much of Central Alabama. The latest satellite imagery has a good convergent low level flow intersecting a thunderstorm outflow area from Carrollton to Fayette to Haleyville. The surface warm front from a few days ago has moved northward and generally dissipated. As would be expected, this moisture gradient is also the gradient for many of the severe weather parameters. Therefore, added a small risk of severe storms with damaging winds and large hail. We may also be affected by outflows from activity upstream in Mississippi later this evening. The drier air south is capped and have the risk confined to northwest areas this evening. 75 --Marginal Risk of severe storms on Monday-- The main focus will turn to what happens with a massive MCS moving through Southeast Texas and the far Northwest Gulf of Mexico early Sunday afternoon. Low-level trajectories will favor a portion of this complex bowing toward the northeastward/eastward into Louisiana and Mississippi. Of course forecast models won`t exactly handle MCSs with precision, and guidance is varied regarding the status of this feature as it approaches/moves into our area. The HRRR continues to be the most robust, with several other short-term/high-res models indicating a weakening MCS as it moves through Mississippi overnight. Even with a more active convective signal, the HRRR redevelops new storms as instability values climb post sunrise. The rest of the guidance suite also shows renewed convection through Monday with the HREF/ARW/NMM/NAM on the same boat. Diffluent flow from an upper low centered toward our west will overspread Central Alabama on Monday atop surface-based CAPE of ~1,000 to 2,000 J/kg and bulk shear around 35 knots. There will probably be some outflow boundaries present as well. Depending on the mode of convection, we could observe decent organization and subsequent severe activity. Hazards would include damaging, straight-line winds and hail (perhaps severe-caliber). The tornado risk is seemingly low at this time. Instability becomes elevated atop a low-level inversion heading into Monday evening/night. There will be a period of inactivity as a mid-level dry slot wraps into the region, before some additional showers/storms move through as the core of the upper low moves overhead Monday night into Tuesday. 89^GSatterwhite .LONG TERM... Tuesday through Sunday April 14. Rain chances linger into Tuesday with some wraparound moisture present. Some instability will be present which could result in some thunder, but severe storms are not expected for Tuesday. Dry conditions are forecast Wednesday and Thursday. A potent shortwave and strong surface low moving through the Midwest will send a cold front through Central Alabama Thursday night and Friday. Forcing and moisture will be sufficient for showers to develop along the front, but limited moisture return will result in only very weak instability. Therefore severe storms are not expected at this time for Thursday night, but will continue to monitor given the strong wind fields. Another strong shortwave will move towards the area Sunday April 14. This system could bring a threat for severe storms depending on moisture return in the wake of Thursday night`s system and subtropical jet influence. 32/Davis && .AVIATION... 00Z TAF Discussion. We start off the period with VFR at all terminals. Lower ceilings will redevelop after 06z tonight and mainly be MVFR, but a few areas of IFR are possible especially south and where it rains. The forecast complications go up thereafter as an upper trough approaches from the west. Mentioned VCSH/PROB 30 TS just before daybreak. The position of small scale boundaries are still TBD and this will have affect on when and how long thunder remains in the forecast on Monday. But overall, chances of rain and thunder are high. Held the MVFR ceilings the entire period due to chaotic atmosphere on Monday. South to southeast winds will prevail, rather light tonight and around 8-9kts Monday. 75 && .FIRE WEATHER... Less thunderstorm coverage is expected today, but moisture values do increase. Therefore, relative humidity values remain high. Showers and thunderstorm chances increase overnight and Monday as more convective systems affect the area. Winds will increase to around 12 to 14 kts during the afternoon and then drop back to 8 kts this evening. && .PRELIMINARY POINT TEMPS/POPS... Gadsden 62 74 58 76 51 / 40 90 50 40 0 Anniston 65 77 59 77 54 / 30 90 50 50 0 Birmingham 65 77 62 79 56 / 40 100 50 40 0 Tuscaloosa 66 77 60 79 56 / 70 100 50 30 0 Calera 65 77 60 76 55 / 40 90 50 50 0 Auburn 63 76 62 76 56 / 30 90 50 60 10 Montgomery 66 79 62 79 56 / 40 90 50 60 10 Troy 66 79 62 77 57 / 30 90 50 60 20 && .BMX WATCHES/WARNINGS/ADVISORIES/... None. && $$
Area Forecast Discussion
National Weather Service Columbia SC
802 PM EDT Sun Apr 7 2019 .SYNOPSIS... A low pressure system will move across the Deep South resulting in numerous showers and thunderstorms Monday and Tuesday. There is potential for severe storms on Monday into the evening. Dry weather is expected Wednesday and Thursday with the next frontal system approaching the area late in the week. Temperatures near or above normal are expected over the next 7 days. && .NEAR TERM /UNTIL 7 AM MONDAY MORNING/... IR satellite imagery shows low pressure in eastern Texas with a large area of showers and thunderstorms over the western Gulf States. Network WSR-88D imagery indicates showers and isolated thunderstorms northwest of the forecast area along the warm front. With the loss of heating much some of the low cloudiness has begun to dissipate however expect low clouds to develop again during the early morning hours. Southerly winds overnight will continue advecting moisture into the area with the high res models indicating a few minor short waves triggering showers overnight. As such have remained with slight chance to chance pops over mainly the western Midlands and CSRA overnight. With low clouds developing overnight and winds remaining 5 to 10 mph fog threat will be low. Low temperatures tonight will be in the low to mid 60s. && .SHORT TERM /7 AM MONDAY MORNING THROUGH TUESDAY NIGHT/... There is potential for severe thunderstorms to develop in the Southeast on Monday and move into the Midlands and CSRA during the late afternoon or evening. The main threats will be damaging wind gusts and hail. An upper-level low will move into the lower Mississippi River Valley on Monday as a mid-level ridge shifts east, allowing SW flow to develop over the Southeast. Warm, moist advection will support thunderstorm development along the remnant boundary of the previous day`s convection. Thunderstorms should move across the Deep South and into the forecast area during the late afternoon or evening. The environment favors the development of organized convection. HREF SBCAPE probabilities suggests that SBCAPE values between 1000 J/kg to 2000 J/kg are likely across the Midlands and CSRA by mid-afternoon. 0-6km bulk shear values of 25 to 35 kts and moderate instability suggests that damaging wind gusts will be a threat and are marginal for supercell development. There are some significant differences in the amount of mid-level dry air between models. This leads to large differences in the WBZ height and limits confidence in the threat of large hail. We cannot rule out an isolated tornado threat given the low LCL heights and marginal low level shear values. Although the strongest helicity values should remain north of the Midlands away from the greatest instability, limiting the threat. Showers and thunderstorms are likely to continue into the evening due to continued deep moisture advection and multiple shortwaves passing over the forecast area. Overall the chance for rain is high with PoP values generally ranging from 70 to 90 percent Monday afternoon and overnight. Lows will be in the 60s. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... The main upper trough and associated surface low should push through the region Tuesday and Tuesday night. The pattern of showers and thunderstorms should continue through Tuesday. Overnight the chance for rain should diminish once the upper trough moves east. Dry and warm conditions return to the Southeast by midweek with highs in the mid 70s to around 80 degrees. The next frontal system will approach the area near the end of the long term period. Although the main surface low should lift quickly northward causing the front to slow as it moves into the Southeast, possibly stalling. Limited moisture ahead of the front also supports just a slight chance to chance pops for Friday and Saturday. Above normal temperatures are likely to continue into the weekend. && .AVIATION /00Z MONDAY THROUGH FRIDAY/... MVFR or lower restrictions expected to develop overnight. VFR at the start of the TAF period will deteriorate tonight. Given ample low level moisture will see stratus develop with widespread IFR/LIFR restrictions after 06z. The HRRR and other high resolution models suggest some scattered showers may develop late tonight in Ga and move north into the CSRA and west Midlands toward dawn. After early morning stratus(fog threat lower due to increased boundary layer winds), cigs expected to improve during the late morning with VFR possible around midday. Morning showers possible...but main showers/tstms slated for the afternoon and evening as the air mass destabilizes. Winds will be light southerly overnight then shift to southwest around 10 knots during the morning as warm advection increases. DNL/AGS...VFR early this evening with light southerly winds. Cig/vsby restrictions developing after 04Z. Conditions improving during the morning as southwest winds increase to around 10 kts. Thunderstorm threat increasing after 18Z. EXTENDED AVIATION OUTLOOK...Flight restrictions in stratus and/or fog expected at times, favoring late night and early morning time periods, through Tuesday. Good chance of thunderstorms Monday night. && .CAE WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. && $$
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1159 PM EDT Sun Apr 7 2019 .AVIATION... Surface trough will clear terminals aob 06z with shower activity just west by the start of the forecast period. Lower VFR to MVFR cigs can be expected from moisture wrapping around shortwave disturbance passing to the north. These cigs may hold into Monday morning, especially for KMBS/KFNT. Southwest flow in wake of trough will remain in the 10-15 knot range overnight into Monday with some gusts near 20 knots in better mixing on Monday as direction veers to westerly. This drier west wind will clear out lower clouds as well. For DTW...Cigs aob 5fkt overnight and possibly into Monday morning. Southwest winds will veer to west/southwest on Monday with some gusts into the 18-20 knot range by midday. .DTW THRESHOLD PROBABILITIES... * High for occasional cigs overnight, medium parts of Monday morning. && .PREV DISCUSSION... Issued at 344 PM EDT Sun Apr 7 2019 DISCUSSION... A low pressure circulation is noted on satellite imagery this afternoon lifting northeastward out of Iowa. Modest warm front amplification is occuring to the south and east of this circulation within a favorable zone of stretching deformation. The warm front, with help from right entrance region dynamics aloft, will lift directly northward across the cwa now through 00Z this evening. Recent forecast data has been extremely bearish with the coverage/likelihood of precipitation both this afternoon and evening. Latest radar mosaic clearly points to best moisture transport vector now veering through TN and into West Virginia. Upstream surface observations have been void of much precipitation across central and northern Indiana outside of some rogue 10SM sprinkles. Given the radar trends, the lack of any true deep moisture above 5.0 ft agl, and modest frontogenesis within lead isentropic wing the decision has been made to roll back PoPs further this afternoon and evening. A chance PoP or scattered showers is a more apt narrative. The better potential will likely fall in the 02- 04Z time window as a secondary ribbon of 875-600mb theta e content will spiral off of old midlevel cyclonic circulation and push directly across Southeast Michigan. The signal even exists that an attempt at true surface based warm sector, highest surface dewpoints, will overspread the area. RAP based soundings have remained the most optimistic with regards to convective potential suggesting warm sector tounge may be good enough to bypass midlevel stability and result in some fleeting convective depths in excess of 20 kft agl. Best potential for a thunderstorm will also be in the 02- 04 time window. Wind shift and deeper column dry air advection will push into the state just ahead of 06Z tonight in response to subsidence wake of passing shortwave. Plan view progs are clear in its depiction of drier air. Model soundings show loss of saturation in the lowest 5 kft agl the latter half of the night. This will set the stage for rapid clearing late tonight with daytime insolation on Monday. Fast zonal flow with organized southwesterly gradient component will help daytime temperatures respond on Monday. Easy decision to go a couple of degrees warmer than guidance for the Monday forecast, upper 60s to lowre 70s. Conditiions will feel ideal for spring with a modest west wind of 15 to 20 mph. Interesting shortwave is forecasted to track through the northern Great Lakes Monday night. Trajectory of inbound upper level jet streak will result in favorable bullwhip orientation and very dynamic PV maximum. Phasing of impressive NW Ontario midlevel coldpool within subsidence region of passing shortwave is indicative of the background synoptic scale forcing available. Current indications support ascent and precipitation potential primarily north of M 46. High theta e content in the lowest 5 kft agl ensures rainfall. A pacific wave is projected to travel across the southern Rockies Wednesday morning and will aid in developing and strengthening a low pressure system through the day. Advancing wave and developing low will amplify a trough across the western U.S. which in turn will support ridging across the Midwest/Great Lakes. This dynamic system will be the focal point for potential rain/wintry mix/snow & gusty conditions, as the low travels from Kansas towards Wisconsin late Wednesday through Friday. To start, advancing warm air/isentropic upglide will bring the chance for precipitation late Wednesday into Thursday morning. The initial onset of precipitation may start out as a wintry mix/snow as bulk of the thermal profile remains below freezing. The advancing warm air will quickly warm the column and transition any wintry precipitation over to rain by the late morning hours. Impressive surge of warmer air will advance across SE MI through Thursday afternoon (h850 of -3C 00Z Thu rising to 9C by 18Z Thu) and will assist in in supporting surface temperatures in the 50s and 60s. Thursday afternoon does exhibit a large ensemble spread regarding placement of low and thus temperature spread, so additional tweaks will need to be made in the coming days. Otherwise, surge of warmer air will come with a brief period of dry weather late Thursday, but will be short-lived as the passage of a cold front will bring a renewed chance for rain and thunderstorms late Thursday into Friday morning. Strong pressure gradient will also bring gusty conditions on Thursday. An expansive dry slot will then fill in Friday afternoon and will diminish rain chances as temperatures fall through the day. Steepening low-level lapse raid will aid in pulling down strong winds aloft, bringing a second day a gusty conditions with gusts possibly exceeding 30 mph. Advancing cold air will bring a period of below normal temperatures into the weekend as surface high pressure settles over the Ohio Valley. MARINE... A weak low pressure system will track northeast across the central Great Lakes this evening and into tonight, bringing with it scattered rain showers and possibly a rumble of thunder to western Lake Erie and Lake St. Clair. East to southeast winds over Lake Huron will be moderate at times the remainder of today with gusts 15- 20 knots. Across Lake St. Clair and western Lake Erie, winds will be more south to southeasterly in direction and lighter. Winds will veer southwest and eventually westerly behind a cold front passage late tonight and into Monday, but remain light with a weak pressure gradient across the region. A secondary cold front and surge of colder air will arrive Tuesday with gusts increasing to 20-25 knots over Lake Huron. Flow will then veer northeasterly and increase to near gales over portions of Lake Huron heading into the middle of next week as strong low pressure develops in the central Plains. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. Lake Huron...NONE. Lake St Clair...NONE. Michigan waters of Lake Erie...NONE. && $$ AVIATION.....DG DISCUSSION...CB/AM MARINE.......IRL You can obtain your latest National Weather Service forecasts online at
Area Forecast Discussion
National Weather Service Hastings NE
721 PM CDT Sun Apr 7 2019 ...Aviation Update... .SHORT TERM...(This evening through Monday) Issued at 351 PM CDT Sun Apr 7 2019 Aloft: Aircraft obs and RAP dynamic tropopause analyses show low- amplitude flow over the CONUS. A trof extended from MN-TX with modest ridges over the Ern and Wrn USA. Low-amplitude will remain over the CONUS thru Mon with WNW flow over the Cntrl Plns...but the Wrn ridge will amplify a bit as a trof approaches the W coast. Surface: A very wk cool front moved thru this AM. The 850 mb thermal trof was already E of the CWA. A small area of wk high pres was building into NEB/KS. A wk low was forming over MT. The high will depart to the S while this low crosses ND tonight. As this occurs... the associated wk cool front will drop into Wrn NEB. This front will cross the CWA tomorrow with a small area of wk high pres moving in after 17Z. Tonight: A bit of thin cirrostratus and possibly a few altocu will move thru...but overall mostly clr. Another very mild night. Lows should be in the 30s in early Apr...but instead they`ll be in the 40s. Mon: Another mostly sunny/very warm day. A bit brzy...espcly over the SW 1/3 of the CWA. Can`t rule out some near-critical fire wx down in Rooks county. RH is currently fcst around 25%. .LONG TERM...(Monday night through Sunday) Issued at 351 PM CDT Sun Apr 7 2019 Aloft: The Wrn ridge will move E and crest over the Cntrl Plns Tue as a deep trof moves into the Wrn USA from the Pac. This trof will cont E Tue night and be over CO/NM Wed. This trof will induce lee cyclogenesis with a low forming and deepening right over the CWA Wed night. Clustering of the global mdls suggest this low will move into Wrn KS 00Z/Thu and then head ENE into Ern Neb by 00Z/Fri. This low will depart the rgn and head to LkSup Fri with cyclonic WNW flow here. Meanwhile...another shrtwv trof is fcst to dive down the back side of the newly established Wrn USA longwave trof. As this trof heads thru the Desert SW Sat...a shrtwv ridge will move thru here. There is quite a bit of spread btwn the NCEP and international deterministic mdl suites. The GEFS mean supports the slower EC/GEM solutions. It conts to look like the Desert SW trof will probably head E into the Srn Plns Sun...vs heading NE into the Cntrl Plns. Surface: The wk cool front that moves thru Mon will become stationary from NW-SE acrs NEB/KS. The temp grad will strengthen acrs that front Tue as lee cyclogenesis ensues over Ern CO. Mdls cont to fcst this front to sink S Tue night...forcing the lee low S and favoring a track acrs KS. The last 5 EC runs have been further S into KS. The GEM runs the furthest N near I-80 with the GFS/GFS-FV3 runs in between near the state line or Nrn KS. While there are minor timing/location diffs btwn the EC/GFS runs...they all come together close to OMA by 12Z/Thu. So even the GFS runs (while not as hvy as the EC) support accumulating snow. The deep sub-985 low will occlude over Ern NEB Thu. High pres will slide into the area Fri-Sat as the low heads to the GtLks. The next low should form well SE of the area next Sun. Temps: Contd way warmer than normal Tue. Wed there is tremendous uncertainy with the front bisecting the CWA. There will probably be a 25-30F temp gradient from N-S. Thu much colder than normal. Fri-Sat will also be considerably cooler than normal...espcly where substantial snow falls. Sun temps should return close to normal. As for sensible wx with the upcoming storm... Little has changed from our prvs thinking. There will probably be little or no precip in the warm sector while it is over/near the it will be capped by an uncontaminated EML that will be advected off the Desert SW and wrapped into this system. Some elevated shwrs/tstms will probably develop N of I-80 Tue night into Wed AM. Right now we do have a chance of shwrs/tstms expanded acrs the entire CWA during the day Wed. This is probably overdone. If the NAM/GFS are right...there is a slight chance that some isolated shwrs/tstms could occur over the SE 1/2 of the CWA at the triple pt where the dryline intersects the sagging cold front. The NAM/GFS scenario would also result in significant fire danger and probably Red Flag Warnings behind the dryline. If the EC wx won`t be a concern and warm sector tstms probably won`t either. A large shield of stratiform precip will evolve on the cold side of the front...and as the low moves by the deformation zone is expected to move in from NW-SE Wed night into Thu. Rain will move in and change to snow...and the snow could be hvy. The occlusion over Ern NEB depicted by the last 5 EC runs is disconcerting because it packs the isobars. EC and GFS 850 mb winds are fcst 50-55 kt. That would produce blzd conds with significant blowing/drifting. The Thu AM commute is looking rough! Snow: we will probably not see accums in our CWA as high as the Sandhills...but believe we could still see a swath of 3-6" bounded by an area of 1-3". Drifts 3-5 ft high will be possible given the expected strength of the winds. Suggest keeping a close eye on the fcst and be prepared to alter plans and take necessary precautions. && .AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Monday) Issued at 720 PM CDT Sun Apr 7 2019 General overview: High confidence in VFR ceiling/visibility through the period, withonly limited high level cloud cover at worst. That leaves at- times breezy and directional-shifting winds as the main on for more details. Winds: The lightest winds of the period will occur right away this evening, as a passing ridge axis promotes a light/variable regime. Then late tonight, a light-but-steady south-southwest breeze will kick in. During the daylight hours Sunday, a passing surface trough will promote steadily shifting and increasing breezes, with direction transitioning to northwesterly and sustained speeds increasing to around 15KT/gusts to around 20KT. The overall- strongest breezes should focus 15-22Z, before sustained speeds ease down closer to 11KT by the last 1-2 hours of the period. On one final note, there are hints of some marginal low level wind shear (LLWS) mainly during the 09-15Z time frame. However, with the shear magnitude currently expected to average under 30KT, and with any possible LLWS concerns well beyond these first 6 hours, will defer to next TAF issuance to take another look for possible inclusion. && .GID WATCHES/WARNINGS/ADVISORIES... NE...None. KS...None. && $$ SHORT TERM...Kelley LONG TERM...Kelley AVIATION...Pfannkuch
Area Forecast Discussion
National Weather Service Grand Rapids MI
1022 PM EDT Sun Apr 7 2019 LATEST UPDATE... Update .SYNOPSIS... Issued at 314 PM EDT Sun Apr 7 2019 - Widely scattered showers and a few thunderstorms are expected this evening (mainly from 6-10 PM) with locally heavy downpours as the main threat. - A cold front will swing through Monday evening along which showers or even brief gusty winds are possible. - An active period is expected from Wednesday night through early Friday with everything from wintry weather to thunderstorms possible. && .UPDATE... Issued at 1023 PM EDT Sun Apr 7 2019 The threat of thunderstorms has for the most part ended as the cold front is currently moving through our CWA with several bands of showers. The better instability remains south of I-94 and it will not be brought back north ahead of the cold front. There have been some brief heavy rain showers and a few showers did have gusty winds thanks to the dry air near the surface as the showers moved in but for the most part wind gusts stayed under 35 mph. Rainfall has mostly been in the 0.30" to 0.50" range (based on radar and very numerous mesonet observations) west of US-131 and north of Grand Rapids. West of US-131 from GRR south to I-94 it was more in the .20" to .30" range, and east of the office mostly under a tenth of an inch. In any event the showers will be out of the area by midnight. Then we have to watch the fog near Lake Michigan to see how extensive it gets. The HRRR, RAP and NAM12 show dense fog over the Lake Michigan overnight that for the most part says over the Lake and may impact areas near and west of US-31. We will monitor this. Enough dry air moves in by midday Monday to clear the skies and thanks to the next cold front`s warm advection pattern we may well get close to 70 degrees inland of US-131 again in the afternoon. So bottom line showers ending by midnight than just mostly cloudy overnight with fog near the lake shore. && .DISCUSSION...(This evening through next Sunday) Issued at 314 PM EDT Sun Apr 7 2019 Apologies for a longer-than-average discussion, but there`s a lot to cover. Overall, the threat for widespread high-impact weather is low but there are plenty of opportunities for "sneaky" events over the next few days. We continue to closely monitor trends this afternoon as a well- defined vorticity maxima in western Wisconsin continues tracking northeast. Broken cloud cover is leading to modest destabilization across parts of Indiana and Illinois, with a warm front delineating dew points in the upper 40s and mid to upper 50s now inching over the southwestern Indiana/Michigan border. With little to no convective inhibition and broad surface wind confluence over eastern Iowa, we expect widely scattered showers and a few thunderstorms to develop out of the bubbling shallow cumulus field over far northwestern Illinois over the next few hours with the leftovers progressing east/northeastward toward Lower Michigan this evening (between 6-10 pm). Forecast thermal soundings continue to show bullish instability in our neck of the woods, but the overall "shape" of the temperature curves (e.g. tall and skinny CAPE) suggests relatively weak/slowly evolving updrafts are to be expected across western Lower Michigan with greater "intensity" as one gets closer to the Indiana border. There`ll be a narrow window of time right around sunset and along I-94 when the low- level flow will increase which may provide a boost to the activity, but by and large the threat for a strong storm remains highly conditional and highest well to our south. The main threat with the activity (with or without thunder) will be locally heavy downpours as PWATs increase to around 1". Low-level moisture will remain in place tonight favoring the development of a low- level stratus deck (as opposed to fog due to gusty winds just above the surface). The exception may be along the lakeshore as westerly winds may push marine fog into lake- bordering counties. Honestly confidence is low in such a scenario but any reduced visibilities are likely to be more localized than not. After a muted start to temperatures on Monday, clearing skies are expected during the late morning/early afternoon hours which will help readings jump into the upper 60s to lower 70s especially south of I-96 and away from the lakeshore. Tomorrow will unfortunately be the last day in our warm stretch as a potent surface wave drags a cold front through Lower Michigan by evening. Various CAMS continue to suggest an arc of diurnal showers may develop along the front Monday afternoon in central Wisconsin though confidence is low on whether they`d hold together into Lower Michigan. Considering low-level winds along and behind the front will be strong, a low-end chance for a burst of gusty winds (35-45 mph) along the front is possible, especially if the showers hold together. Relatively quiet, though cooler, weather is then expected Tuesday with highs in the upper 40s to lower 50s as the aforementioned front stalls just south of the Michigan/Indiana border. Attention then turns to the well-advertised strong low pressure system poised to track through the central United States through the western Great Lakes Wednesday into Thursday. Ensemble model guidance aided by evolutionary details in deterministic solutions is leading to increasing confidence that the system will impact Lower Michigan in two waves. The first wave will be Wednesday night into Thursday in the form of wintry precipitation as a warm front lifts northward across the Great Lakes. By Thursday afternoon, much of the area should be in the warm sector of the low pressure system with the second wave being a round of showers and possibly thunderstorms Thursday evening/early Friday morning. There may also be a periods of gusty winds from Wednesday through Thursday with the ECMWF ensemble mean peak wind gusts broaching 35kts across much of the area. All in all, we`re growing confident in those "broad ideas," but there are still several outstanding questions the two most important being 1). If the warm front stalls somewhere in Lower Michigan, would hefty snow totals become possible? and 2). If the cold front swings through during or just after peak heating Thursday (notwithstanding other mesoscale details and the progged strong wind fields), would a round of strong to severe storms become possible? We have ample time to address these questions over the coming days but the main message right now is to expect active weather this week. For potential hydrologic impacts from this system, see the hydrology discussion below. As the system departs the Great Lakes Friday, residual showers (perhaps in the form of snow) are possible through early Saturday morning. Another storm system is then expected to track through the U.S. early next week, with the ensemble solution space including scenarios in which portions of Lower Michigan see another round of precipitation. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 733 PM EDT Sun Apr 7 2019 I expect an area of showers and a few thunderstorms to impact all of the TAF sites (MKG and GRR should miss the thunderstorms but still get heavy rain showers) between now and 03z as the primary system moves through the area. Winds have gusted to around 30 knots in some of the storms this evening. Once that front comes through I expect dense fog to move into MKG by 06z and hold until around sunrise when the drier air will mix down and clear the sky by midday. All of the TAF sites will see the IFR cigs but there is a question as to how far inland the fog gets. I have it reaching GRR for a few hours then mixing out. The fog may reach AZO and BTL, that will have to be watched. Just beyond our TAF period another cold front comes through and it may have mover convection assoicated with it. && .MARINE... Issued at 314 PM EDT Sun Apr 7 2019 Patchy dense fog is possible tonight through Monday afternoon, though winds and waves are expected to remain below 22 kts and 4 ft, respectively. A brief period of strong northwesterly wind gusts to 25 kts is possible Monday after sunset. After a relatively quiet Tuesday and early Wednesday, periods of strong winds (at times with gale force gusts) are expected from late Wednesday through Friday with large waves extending into the weekend. An extended Small craft advisory will likely be needed from Wednesday night onward. && .HYDROLOGY... Issued at 314 PM EDT Sun Apr 7 2019 Rain chances this afternoon and evening should have little to no impact on area rivers as precip amounts stay limited to around one- quarter inch. The next system that may be somewhat impactful to rivers will arrive in the form of rain and/or wet snow Wednesday afternoon and evening and last through Friday. Unfortunately with temperatures expected to largely stay above freezing, any snowfall should melt on impact and therefore not slow river responses. Current guidance suggests precipitation amounts on the order of 1.00 to 1.25 inches with the highest totals possible for the Muskegon basin. No flooding is expected, however we may see some rivers crest near or above bankfull. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. LM...None. && $$ UPDATE...WDM SYNOPSIS...Borchardt DISCUSSION...Borchardt AVIATION...WDM HYDROLOGY...ANH MARINE...Borchardt
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1041 PM EDT Sun Apr 7 2019 .SYNOPSIS... As moisture continues to flow into the region, an upper-level low pressure system will approach the area from the west on Monday, crossing the area by Tuesday morning. There continued to be the best chance of organized thunderstorms Monday afternoon and evening. Drier high pressure will return mid week before a cold front approaches from the west late in the week, that will bring more chances for showers and thunderstorms. && .NEAR TERM /THROUGH MONDAY/... As of 1030 pm Sunday: As deep convection has been dissipating as expected across the southern Appalachians this evening, new scattered convection has initiated within the past couple of hours across the SC Piedmont at the nose of an area of lingering ~500 J/kg sbCAPE. This activity has been gradually expanding in coverage and intensity with time, with the stronger cells likely producing small hail. However, as it moves into an increasingly stable air mass near the NC/SC border, it should begin a diminishing trend prior to midnight, with the HRRR showing it completely dissipating by that time. After that, the overnight hours should be rather quiet, and only token 20-30 pops are carried during that time, mainly in western areas. A relative lack of mid to high clouds tonight will likely allow for some combination of low clouds and/or fog (possibly dense) to develop/expand in coverage overnight, especially east of the mountains. An upper low currently over Texas will slide east into the Lower Mississippi Valley Monday providing increasing support for shower and thunderstorm development across the region. Moist southerly flow ahead of this feature will continue to destabilize the atmosphere with CAPE values on the order of 1-2K J/kg likely and with enough sunshine early in the day (as indicated in some models including the NAM), CAPE values may approach 3K J/kg across the I-77 corridor. A vort lobe will eject east ahead of this feature and pass through the region (from SW to NE) Monday morning into the afternoon and likely act to kick off shower and thunderstorm activity across the region. Modest low level shear (although near unidirectional) combined with cool/dry air aloft (WBZ ~1K ft and DCAPE >500 J/kg) will combine to support the potential for strong to severe thunderstorms (greatest threats being damaging winds and large hail) focused east of the mountains (see SPC day2 outlook for the latest areal coverage). In addition to the threat for strong thunderstorms, PWs in excess of 1.5 combined with both convective and orographic lift along with training of cells (thanks to unidirectional flow) over the region may lead to at least some minor flood issues (we fall within a WPCs marginal flood risk). However, the recent period of below normal precip reduces this risk somewhat. Rainfall totals through Monday evening are expected to be generally 1-2 inches with locally 3 inches across the escarpment and in areas that experience training of thunderstorm activity. Above normal temperatures (especially overnight) will continue through the near term with lows generally in the 60s and highs in the 70s && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/... As of 250 PM EDT Sunday: An unsettled weather pattern will carry from the near term through into the first half of the short term forecast period, with a drying trend expected on Wednesday. With an upper closed low slowly pushing eastward through the southern MS Valley/Gulf states Monday night into Tuesday within split flow, expect ongoing widespread showers and thunderstorms across the area Monday night, as a cold front gradually propagates eastward through the Carolinas, before it becomes temporarily stationary just east of the FA. Would not entirely rule out the lingering potential for severe thunderstorms at the beginning of the fcst period (primary threat being wind), but given the gradual loss of daytime heating and the better instability/shear exiting the FA, anticipate thunderstorms will become sub-severe as they carry into the overnight hours, with ongoing showers as well, through into Tuesday. With PWAT values climbing to near 1.25-1.5, would not entirely rule out minor flooding as well, especially in heavier downpours, with portions of the area noted in a marginal risk for excessive rainfall from WPC. With ongoing isolated to scattered showers and thunderstorms on Tuesday, latest guidance progs the slow-moving upper closed low across the Gulf States to become an open wave into Tuesday afternoon, shifting eastward away from the Carolinas into early Wednesday, while at the same time, a secondary weak cold front pushes through. As a result, expect rain chances to end from NW to SE Tuesday afternoon into the nighttime hours, as a drying trend begins. On Wednesday, expect dry conditions to prevail with clearing skies and upper riding over the central CONUS begins to shift eastward ahead of the next approaching system. Temperatures throughout the period will be above normal. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... As of 300 PM EDT Sunday: Conditions will be dry at the beginning of the extended fcst period, with weak sfc high/weak ridging aloft in place and a stationary boundary just south of the Carolinas. As sfc high pressure shifts offshore through the morning hours, SW flow returns into Thursday afternoon as a closed upper low and parent sfc low propagate northeastward from the central/northern plains to the Upper Midwest into Friday afternoon. As these features move, the boundary to the south will lift through the area as a warm front overnight Thursday into early Friday, as it`s associated cold front pushes through the area Friday afternoon into Saturday. As a result, expect rain chances to return as early as Thursday, continuing through into Saturday. With the cold front and notable available instability/upper dynamic support, would not entirely rule out isolated thunderstorms Friday afternoon as well. Temperatures will remain above normal. && .AVIATION /03Z MONDAY THROUGH FRIDAY/... At KCLT and elsewhere: Showers and a TS or two continue to impact portions of GA and far western NC this evening, while a few showers were also beginning to develop across portions of Upstate SC. That being the case, cannot rule out a shower passing near the Upstate SC terminals and KAVL/KHKY later this evening or early in the overnight. However, coverage should gradually trend downward over the next few hours. Otherwise, rich low level moisture, light winds and generally clear mid/upper levels should allow low stratus to fill in at most terminals beginning late this evening. Also cannot rule out a redux of the dense fog that was seen Sunday morning, and in fact, tempos for 1/4SM have been included where confidence is highest (KCLT and KHKY). However, cannot rule out VLIFR conditions at the other terminals. Convective chances increase again late morning into the afternoon, with numerous to widespread coverage of showers and storms expected during the afternoon, as a cold front approaches from the west. Winds will generally be light S/SW overnight, increasing to around 10 kts, with higher gusts possible Monday afternoon. Outlook: Periods of low cigs, patchy fog, and convection will remain possible across the area into Tuesday. Drying is expected late Tuesday through Wed, before another front approaches late in the week. Confidence Table... 02-08Z 08-14Z 14-20Z 20-00Z KCLT High 81% Med 72% High 91% High 100% KGSP Med 78% Med 63% Med 78% High 100% KAVL Med 75% Med 62% High 98% Med 79% KHKY Low 59% Med 71% High 84% High 97% KGMU Med 70% Low 57% High 94% High 100% KAND High 97% Med 67% Med 78% 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...CSH/WJM NEAR TERM...JDL/Munroe SHORT TERM...SGL LONG TERM...SGL AVIATION...JDL
Area Forecast Discussion
National Weather Service Indianapolis IN
1059 PM EDT Sun Apr 7 2019 .UPDATE... Aviation sections updated && .SYNOPSIS... Issued at 328 PM EDT Sun Apr 7 2019 A cold front will bring scattered showers and thunderstorms to central Indiana tonight into Monday. A strong low pressure system will bring more rain chances to the area Wednesday through Thursday night. Yet another system will bring more rain chances for the second half of next weekend. Temperatures will stay above normal through much of the work week, then turn to below normal. && .NEAR TERM /Overnight/... Issued at 941 PM EDT Sun Apr 7 2019 Surface analysis late this evening shows broad cyclonic flow across Indiana with Low pressure centered over Lower Michigan. A cold front stretched SW across Illinois to SW Missouri. WARM SW flow was in place across Indiana. Radar shows a few showers with isolated thunder strikes north of LAF and NW of HUF. More organized precipitation was found across Western Illinois...ahead of the cold front. HRRR continues to suggest a eastward propagation of the the cold front and associated precipitation now over Western Illinois. Time heights suggest best moisture and lift overnight as these features arrive and pass. Thus have trended short term pops (next 1-2 hours) higher in areas where current radar trends suggest propagation of ongoing storms...but best and more widespread pops will be expected overnight as better forcing arrives along and ahead of the cold front overnight. && .SHORT TERM...(Monday through Wednesday) Issued at 328 PM EDT Sun Apr 7 2019 Models are close enough that the model blend initialization was accepted for most items. The cold front will hang around the southern forecast area on Monday, so will keep some low PoPs there into early afternoon. Otherwise dry conditions can be expected through Monday night. Another cold front will move through on Tuesday, but there won`t be any moisture to work with. Will keep the area dry. On Wednesday, a warm front will move through area ahead of a deepening surface low well to the west of the area. There could be enough forcing and moisture across the northern forecast area for a few showers, so kept the initialization`s low PoPs. However, confidence is low at this time. The initialization`s temperatures look reasonable. && .LONG TERM /Wednesday Night through Sunday/... Issued at 240 PM EDT Sun Apr 7 2019 Ensembles indicate a progressive and active extended period. One significant trough is expected to lift out from the Plains into the Great Lakes early in the period, while another trough may move into the Midwest by next Sunday. Ensembles in fairly good agreement in the best precipitation threat with the first system will be on Thursday and Thursday night. Will go with PoPs for showers and thunderstorms in those periods to cover the first system. System may be quite dynamic, with long range operational models suggesting an associated mid level jet around 100 kts. Ensembles suggest the precipitation threat with the second system may arrive as early as Saturday night. Will go with PoPs for Saturday night into Sunday with this second system. && .AVIATION /Discussion for the 080300Z IND TAf update/... No significant changes to the IND TAF. VFR Conditions continue. TSRA north of IND have continued to blossom, but should remain North of the TAF sits until the overnight hours when more convection over Central Illinois should arrive over Central Indiana. Previous Discussion Below /Discussion for the 080000Z Tafs/... Issued at 741 PM EDT Sun Apr 7 2019 Mainly VFR conditions will be expected overnight. Some brief MVFR conditions will be possible as a weak cold front and associated cold front pushes across Indiana. HRRR suggests sct rain showers pushing across the state along and ahead of the front and MVFR Cigs will be expected with any sct shra. Weak cold air advection and time heights suggest lingering lower level moisture in the wake of the front on Monday morning...which should lead to some continued MVFR Cigs in the morning. As heating and mixing continues through the day...dry air and subsidence is expected to return leading to VFR cigs by the afternoon. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...50 NEAR TERM...Puma SHORT TERM...50 LONG TERM....JAS AVIATION...JP
National Weather Service Jackson KY
1040 PM EDT Sun Apr 7 2019 .UPDATE... Issued at 1040 PM EDT SUN APR 7 2019 The latest radar trends, and the NAM12 and HRRR models, are all indicating that we will see a lull precipitation for the next several hours. All indications are that the next round of precip will not get into the area until after 7Z. The forecast grids were updated to reflect this as was the updated zone forecast text product. At this point we are not anticipating any severe weather tonight, so the hazardous weather outlook was updated to reflect this trend. UPDATE Issued at 807 PM EDT SUN APR 7 2019 Updated the forecast to remove a late afternoon period from the zone forecast text product and to incorporate the latest obs into the hourly forecast grids. Overall the forecast is on track with a few showers currently moving across the southern and southeastern portions of the area. Precipitation probabilities are on track as well, with the next round of rainfall not expected to make it into the area until late tonight. && .SHORT TERM...(This evening through Monday night) Issued at 412 PM EDT SUN APR 7 2019 Current surface analysis shows a low pressure system over the borders between South Dakota, Minnesota, Iowa, and Nebraska. At the same time, a deep upper level trough located over the central CONUS will make its way towards the Ohio Valley through Tuesday. Kentucky is currently in the warm sector, with a surface warm front draped over the upper Ohio Valley and a cold front running north to south over the central Great Plains. This has led to the rain showers that affected eastern Kentucky through the afternoon today. Some of these rain showers have been heavy at times, with a few embedded thunderstorms as well. Much of the thunder threat has diminished for the afternoon and current radar shows rain showers moving off to the northeast. A lull in precipitation is expected for early evening before another round of showers will overspread eastern Kentucky overnight with the advancement of a cold front. Instability will be limited, but there will be the potential for a few thunderstorms overnight. Slight chances for storms will persist for the Cumberland Basin region through tomorrow afternoon as well. Showers are expected through the day Monday but will begin to taper off through early Tuesday as the cold front progresses to the southeast. Expected total rainfall from this afternoon through early Tuesday is between 0.75 inches in the north and about 1.5 inches in the southeast. With PWATs over 1 inch, this rainfall estimation seems reasonable. Temperatures this afternoon reached the upper 60s in the Cumberland Basin region and in the mid 70s in the far east. Not expecting temperatures to warm much more due to sufficient cloud cover and recent rain showers. Lows overnight tonight will be well above normal, around 60 degrees, due to the warm front north of the Commonwealth. Highs will be slightly cooler tomorrow, generally in the low 70s, particularly in the east due to FROPA. Lows Tuesday morning will then be in the mid 50s. .LONG TERM...(Tuesday through Sunday) Issued at 417 PM EDT SUN APR 7 2019 The extended portion of the forecast begins on Tuesday with an active and rather progressive pattern in place across the CONUS. Tuesday begins with the sign of a split upper level flow with a trough exiting to the southeast and second crossing the Great Lakes to the north as this feature brings a cold front across eastern Kentucky, and this feature will be exiting east Kentucky Tuesday morning. Thus will see some showers exit the area Tuesday morning. By Tuesday evening, mid level ridging will move over the region. This will be in convection with surface high pressure nosing into the OH and TN Valleys from the southwest. The development of the next system will impact the area for Friday. High pressure nosing into the area will keep eastern Kentucky dry and warm through Thursday. The mentioned system will develop as a strong low deepens over the central Plains and then lifts to the northeast into the Midwest by Thursday night. With a strong warm front developing by Thursday, this will bring precip to southern OH with east Kentucky being in the warm sector Wednesday and Thursday. This as evidence as MOS data will bring middle and upper 70s for highs on Wednesday and Thursday. This setup will bring a strong cold front through on Friday. At this time, a strong gradient will lead to some gusty winds on Friday but also models hint at the boundary shearing out as it tracks across east Kentucky. This setup may lead to less precip and low chance of thunder as the boundary passes the area. Nevertheless, will mention a chance of thunder for Friday as showers will likely exit the area by Friday evening. A tight gradient behind this system will lead to some cooler air accompanying high pressure moving in for the weekend. Thus, will expect temperatures in the low and middle 40s for lows on Saturday and Sunday but highs those days will at least get into the middle 60s. Otherwise, the only concern through the extended will be the feature on Friday with the rest of the extended being warm and dry. && .AVIATION...(For the 18Z TAFS through 18Z Monday afternoon) ISSUED AT 226 PM EDT SUN APR 7 2019 Generally VFR conditions were observed at TAF issuance. The exception to this are in areas where heavy rain showers move over, reducing visibilities. A few embedded thunderstorms are also expected through the afternoon. At this time, only included mention of thunder for SME, LOZ, and SYM this afternoon due to low confidence if sites in the east would be affected. Also accompanying the heavier showers are some gusty winds. However, winds will decrease overnight. Rain showers and the chance for some thunderstorms will continue into tomorrow with the approach and passage of a cold front. Lowered CIGs to MVFR are also expected to accompany cold front passage tomorrow morning. However, recovery to VFR will be likely for most locations by the afternoon. Winds will be out of the southwest this afternoon and through the overnight, but then shift to be more west/southwest and generally be light tomorrow afternoon. && .AVIATION...(For the 18Z TAFS through 18Z Monday afternoon) ISSUED AT 226 PM EDT SUN APR 7 2019 Generally VFR conditions were observed at TAF issuance. The exception to this are in areas where heavy rain showers move over, reducing visibilities. A few embedded thunderstorms are also expected through the afternoon. At this time, only included mention of thunder for SME, LOZ, and SYM this afternoon due to low confidence if sites in the east would be affected. Also accompanying the heavier showers are some gusty winds. However, winds will decrease overnight. Rain showers and the chance for some thunderstorms will continue into tomorrow with the approach and passage of a cold front. Lowered CIGs to MVFR are also expected to accompany cold front passage tomorrow morning. However, recovery to VFR will be likely for most locations by the afternoon. Winds will be out of the southwest this afternoon and through the overnight, but then shift to be more west/southwest and generally be light tomorrow afternoon. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...AR SHORT TERM...CGAL LONG TERM...SHALLENBERGER AVIATION...AR
Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
1046 PM CDT Sun Apr 7 2019 .UPDATE... Issued at 920 PM CDT Sun Apr 7 2019 Made adjustments to POPs for ongoing storms which should begin to wind down after 03z, though did keep thunder mention in til 06z, with just lingering showers after that. Front has made progress through forecast area and as of 02z extended from surface low just north of St. Louis to Vichy to just east of Springfield, MO. Byrd && .SHORT TERM... (Through Monday Night) Issued at 244 PM CDT Sun Apr 7 2019 Still waiting for activity to fire up this afternoon as pre-frontal trof extending from west central Illinois south southwestward towards Springfield, MO as of 19z Sunday slides east. Latest RAP run still showing surface based CAPES between 1500 and 2500 J/kg through early this evening, mainly along and south of I-70 corridor. This combined with deep layer shear increasing to around 35 kts and decent moisture convergence along the trof will see isolated/ scattered storms develop anytime now. Coverage will be sparse but could see some isolated strong to severe storms for portions of eastern MO and western IL through this evening with the main threats being large hail and damaging winds. In the meantime, main cold front is still progged to approach northwestern portions of forecast area by late this afternoon with showers and storms developing in this area by 22z Sunday. Eventually the front will catch up with the pre-frontal trof and merge, pushing the activity southeastward out of the forecast area by 12z Monday, though some lingering showers are possible over portions of southeast MO and southern IL through midday. Dry and mild weather will prevail across the region Monday and Monday night with clouds clearing out by late Monday afternoon. Otherwise, some weak CAA tonight after front moves through with lows in the upper 40s to upper 50s. Highs on Monday will be in the low to mid 70s with lows Monday night in the upper 40s to low 50s. Byrd .LONG TERM... (Tuesday through Next Sunday) Issued at 244 PM CDT Sun Apr 7 2019 Still expecting dry and warmer weather through mid week with highs in the mid 60s to upper 70s each day. Extended models still show decent cyclogenesis over the Central Plains midweek as upper level trough swings through, though have minor differences in placement and timing, so kept NBM blend with increasing chances of showers and thunderstorms beginning Wednesday night through Thursday evening before exiting. With this wound up system, it will be quite breezy on Thursday. Beyond that, colder weather expected for Friday through Sunday with another chance of rain Saturday afternoon through Sunday. Byrd && .AVIATION... (For the 06z TAFs through 06z Monday Night) Issued at 1033 PM CDT Sun Apr 7 2019 A cold front will drop southeastward through the St Louis metro area around 06Z Monday. Most of the showers and storms should also shift east of the taf sites by 06Z Monday with just some lingering VFR cloudiness for the rest of the overnight hours. Little if any cloud cover is expected for Monday and Monday evening. A weak north-northwest surface wind can be expected late tonight after fropa, backing around to a west-northwest direction Monday afternoon and evening as a secondary cold front approaches from the northern Plains. SPECIFICS FOR KSTL: A cold front will drop southeastward through STL around 06Z Monday. Most of the showers and storms should also shift east of STL by 06Z Monday with just some lingering VFR cloudiness for the rest of the overnight hours. Little if any cloud cover is expected for Monday and Monday night. A weak north-northwest surface wind can be expected late tonight after fropa, backing around to a west-northwest direction Monday evening as a secondary cold front approaches from the northern Plains. GKS && .LSX WATCHES/WARNINGS/ADVISORIES... MO...None. IL...None. && $$ WFO LSX
Area Forecast Discussion
National Weather Service Nashville TN
835 PM CDT Sun Apr 7 2019 .UPDATE... FOR EVENING DISCUSSION. && .DISCUSSION... Radar across Middle Tennessee nearly-echo free now that this afternoon`s activity has moved east of the region. The HRRR brings widespread activity back to the mid state after 06Z as both a surface boundary and upper trough approach from the west. The SPC has left most of Middle Tennessee under a slight risk of severe storms for the rest of tonight so any storms that do develop during the early morning will certainly bear watching. The evening sounding from OHX shows a 0-3 storm-relative helicity of 272, with marginal instability and 6.5 C/km lapse rates in the mid- levels. Hourly grids are holding up well and the current forecast appears to be in good shape for now, so no changes are planned at this time. && .AVIATION... 00Z TAF DISCUSSION. VFR conditions until after midnight when additional showers (and possibly a TS) move into Middle TN. Cigs and vis should drop accordingly to MVFR. A second wave is possible during the early afternoon hours Monday, which is likely to further drop cigs. Some IFR is possible in the heavier downpours. Winds will be light and mainly southerly tonight, southeasterly Monday. && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ DISCUSSION......08 AVIATION........Unger
Area Forecast Discussion
National Weather Service Blacksburg VA
1128 PM EDT Sun Apr 7 2019 .SYNOPSIS... Low pressure will shift from the lower MS Valley late tonight slowly to the Gulf Coast states by Monday afternoon. A front will slide from the midwest tonight to over Virginia by Monday evening. This front will slow down over VA/NC/SC while waves of low pressure moving along it from the Gulf Coast to off the coast of VA into Tuesday. && .NEAR TERM /THROUGH MONDAY/... As of 1127 PM EDT Sunday... Showers and a few scattered thunderstorms which had affected far southwest VA into Ashe County NC have since fizzled, as nocturnal stabilization has commenced with nil CAPE noted in SPC mesoanalysis. Other than the activity just crossing the western NC mountains southwest of Caldwell County NC, which may affect Yadkin and Wilkes counties later in the overnight, think we`ll be seeing a lull in shower coverage areawide through much of the overnight hours. Recent high-res convection-permitting models bear this dry trend out as well. Have therefore reduced pops to slight chance pretty much areawide for much of the overnight. However next threat for rain showers is into our southeast WV into Mountain Empire counties as a sagging cold front, now over western OH and central IN, meets up with the approaching disturbance over the northern Gulf Coast states. Showers appear likely to re-blossom as this process occurs, as shown by the incoming 00z NAM and the higher-res guidance, which occurs mainly from Greenbrier through Tazewell County. Looking further south, stratus has begun to develop across a large part of coastal SC into part of the central NC Piedmont south of the Triad/Triangle region. Models do show this high RH layer eventually seeping its way northward into our NC Piedmont counties and into Southside in southerly flow. Will also show a bit more fog/mist than prior forecast into the foothills/Blue Ridge counties given the narrow T-Td spreads, but visbys unlikely to be as low as they were the last couple nights. No significant change made to temps. It should be a pretty mild evening with lows in the 50s to low 60s and dewpoints in the 50s to near 60. Previous discussion from 220 PM Sunday... Weather has been fairly quiet so far today, with main concentration of convection located over KY/TN. One weak disturbance has pushed away from our area, and only a few sprinkles/very light showers showed up on radar with this feature. The 12z models had a hard time with this showing too much precip. The HRRR and RAP seemed more reasonable at least through the afternoon, and overall expecting most coverage with the next wave over southern KY to affect our WV counties after 4-5pm, with limited coverage elsewhere. As that wave slides north of us this evening, expect a lull in activity, but keeping some residual pops around, especially west as low level convergence increases. Still confidence is low on the overall pop for tonight, thinking main shower/storm chances remain west of the Appalachians. Low level air remains moist, and with cloud cover in place, expect temps to not drop too far tonight, so went above guidance, with lows closer to early summer readings, fro the mid to upper 50s in the west to lower 60s east. Monday, the Storm Prediction Center highlight our eastern two-thirds of our CWA with marginal risk of severe, with a slight risk posed over southside VA into the NC piedmont. Upper levels show a closed low over the lower MS Valley early in the afternoon, with several impulses lining up from Arkansas to the mid- Atlantic, while a northern stream shortwave slides toward the Great Lakes. The shear increases ahead of the front, but limited instability due to cloud cover may hinder decent convective development. Models show some potential heating/less cloud cover in the afternoon over the piedmont where the slight risk is, with SBCAPES reaching 1000 J/KG. So will continue to highlight this in the HWO, with the main threat staying damaging wind gusts. Low level helicities are not that high, at least where the best instability is, so overall tornado threat is low for now. Additionally, convective elements in an increasingly moist airmass may bring torrential downpours, such that isolated flash flooding cannot be ruled out but overall threat is low, and mainly limited to the mountains. Temps tomorrow will be dependent on cloud cover and shower coverage, so went cooler than MOS in the west, and near to above MOS in the southeast, where some insolation is possible. Highs will range from the upper 60s to lower 70s in the mountains, to mid to upper 70s east. && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/... As of 215 PM EDT Sunday... Precipitation is expected to remain very widespread across the southern third of the forecast area through Monday evening as moisture continues to stream along a slowing moving cold front. Northern sections of the region near the I-64 corridor may see an end of the precipitation during the late evening hours, however will maintain some isolated/scattered coverage to both mesh better with neighboring forecasts and give credence to those model solutions that aren`t as optimistic in the precipitation ending as promptly. The best potential for thunder is expected to remain south of the forecast area. However, it is not zero for again roughly the southern third of the area through midnight. Precipitation will gradually come to an end for most of the region heading into the early morning hours of Tuesday. The more significant rain will end last across the far southeastern sections of the forecast area. Some isolated to scattered upslope shower activity may develop for a short time across portions of southeast West Virginia and parts of neighboring counties of southwest Virginia. During the day Tuesday, a brief resurgence of isolated showers and isolated thunderstorms may occur across the extreme southern sections of the forecast area. This region will still be close enough to the departing cold front during the peak heating of the day to allow for this possibility. Model solutions regarding the upper low that has been forecast to progress eastward through the Gulf Coast states on Tuesday is continue to trend this feature farther south. As such, our forecast has been reflecting less chance of precipitation associated with it and even less thunder potential. This trend continues with the latest model output. As such, other than the potential resurgence of isolated showers/storms across the far southern sections of the area, no other precipitation will be introduced into the forecast for Tuesday. Tuesday night through Wednesday night, cooler and drier high pressure builds into the region. The most notable item for our forecast will be some gusty winds in the 15 to 20 mph range Tuesday into Tuesday night thanks mainly due to the increased pressure gradient between the low passing to our southeast and the advance of high pressure into the area. Temperatures during this portion of the forecast will trend cooler so that by Wednesday into Wednesday night, temperatures are expected to be near normal for this time of year. Confidence in this portion of the forecast is moderate to high. The general trend of the synoptic pattern looks on track. The greatest uncertainties rest in the location and potential for the heaviest rain and thunderstorm potential Tuesday evening. && .LONG TERM /THURSDAY THROUGH SUNDAY/... As of 1230 PM EDT Sunday... Thursday the area will get a break from the active weather as high pressure settles over the area, and then shifts east to the coast by late Thursday night. Active weather is expected to return to the region on Friday with the approach and passage of a cold front associated with an upper level low pressure system heading eastward through the Great Lakes region. Isolated to scattered thunderstorms are expected to accompany a generous coverage of showers as the front crosses our area, especially during the afternoon hours from around the crest of the Blue Ridge and points eastward. The front is currently expected to make a rapid departure east of the area Friday evening, with perhaps a few lingering showers across eastern parts of the region, ending before midnight. However, our weather pattern only briefly turns dry, before the same cold front, is lifted back north as a warm front by early Saturday afternoon thanks to the low level flow turning southeast in advance of a developing low/trough across Texas. As the Texas low/trough deepens and progresses into the mid- Mississippi Valley, we are expected to experience increasing showers across the region thanks to a prolonged moisture fetch off the eastern Gulf of Mexico. We may be dealing with a period of locally heavy rain that begins on Sunday, and could continue past the conclusion of our Day 7 forecast into the following Monday. Isolated thunderstorms may be possible across parts of Southside Virginia and our neighboring north central North Carolina counties Sunday afternoon. Temperatures on Thursday and Friday are expected to average about 10 to 15 degrees above normal. By Saturday into Sunday readings will decrease to value closer to normal for this time of year. Confidence in this portion of the forecast is moderate. While the overall general trend in the synoptic pattern is fairly confident, the timing factor and specific tracks of the precipitation, amounts, and convective features is not as confident. && .AVIATION /03Z MONDAY THROUGH FRIDAY/... As of 754 PM EDT Sunday... Generally VFR, with intervals MVFR within the Blue Ridge Mountains to persist through 04z. Will be watching a cluster of heavier showers with isolated thunder spread to I-77 corridor between 00-03z. While unlikely to affect the TAFs, aviation interests flying routes in or southwest of this corridor should be aware of lightning potential and turbulence in/around thunderstorms. All told, best chance of rain mainly west of the Blue Ridge through overnight. Will eventually see ceilings degrade to sub-VFR levels at Danville and potentially into Lynchburg, along with intervals of MVFR-type mist at Blacksburg and Roanoke. Best chance of IFR or lower at Danville from ceilings. May have some mist or fog at Danville as well but confidence wasn`t as high on this here as last couple nights given slightly stronger wind speeds. Low clouds/fog may linger into a good part of Monday morning in this area. Winds south 4-7kts through overnight. Low clouds/stratus should burn off by midday toward VFR. However, as main upper- level disturbance approaches our area later in the day Monday, expect a renewed round of showers with embedded scattered thunderstorms as well, mainly for areas south of Route 460. Though confidence on timing is only low to moderate, feel best chance for thunder is between 20-00z and mainly south of Route 460. Have shown VCSH at most TAFs, but include SHRA VCTS to indicate potential for thunder at Danville. May be a few strong thunderstorms capable of hail/wind and local IFR visby in this corridor as well. Overall expect deteriorating flight categories further south one goes into the mid to late aftn hrs. Winds southwest 4-8 kts, locally stronger near thunderstorms. Confidence in ceilings is moderate (lower on timing erosion/lifting), visbys is low/moderate, and high on winds. EXTENDED AVIATION DISCUSSION... MVFR/IFR conditions are possible with scattered showers and isolated thunderstorms through Tuesday. Drier weather and VFR ceilings and visibilities are expected Wednesday into Thursday, though another front looks to bring sub-VFR back into the area late Thursday into Friday. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...AMS NEAR TERM...AL/WP SHORT TERM...DS LONG TERM...DS AVIATION...AL/WP
Area Forecast Discussion
National Weather Service Springfield MO
627 PM CDT Sun Apr 7 2019 ...AVIATION UPDATE... .SHORT TERM...(This evening through Monday) Issued at 238 PM CDT Sun Apr 7 2019 Even though showers and storms have not yet developed, our area remains in the warm sector ahead of an advancing cold front over eastern Kansas this afternoon. Dewpoint temperatures were in the upper 50s to lower 60s, and the latest RAP soundings using the Near Storm Environment Awareness program show current surface based CAPE over 2000 j/kg. 0-6km bulk shear is marginal with values at or below 30 knots. While better low level moisture remains well to our south, think storm development will be possible along the front from later this afternoon through tonight. Monday still looks warm and dry with highs once again reaching the 70s. .LONG TERM...(Monday Night through Sunday) Issued at 238 PM CDT Sun Apr 7 2019 Mainly monitoring trends with the storm system deepening over the central High Plains on Wednesday and moving across our region Wednesday night and Thursday. Initial concern will be increasing southwest winds that will have the potential to gust to over 30 mph, especially Wednesday afternoon and evening. There is pretty decent consistency on the placement of the surface and upper level low over southeast Nebraska Thursday morning, but some differences on precipitation placement. In fact it looks like some areas may get missed altogether on precip as a well developed dry slot is progged to move over our area. For now have maintained very low precip chances as it appears there will be access to gulf moisture. Next concern will be the colder temperatures spilling into our area behind this system on Thursday-Saturday. Both the ECMWF and GFS have the 540 dm thickness line bisecting our forecast area on Friday afternoon. Only slight rebounding in thickness shows up by Saturday morning. Thus confidence remains fairly high in the temperature trends for later this week. Later in the weekend an upper level trough moving across the southern Plains could bring rain to the region during the latter part of the weekend. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Pilots flying in and out of the southwest Missouri airports can expect fair weather VFR conditions over the next 24 hours. A few thunderstorms will develop over the eastern Ozarks, however, they should remain away from the TAF sites. Look for light and variable breezes tonight with no low ceilings or reduction to visibility. Safe Travels. && .FIRE WEATHER... Issued at 238 PM CDT Sun Apr 7 2019 On Wednesday afternoon we could see some fire weather concerns as southwest winds increase to over 30 mph at times while temperatures rise into the 80s and minimum relative humidities fall below 40 percent. && .SGF WATCHES/WARNINGS/ADVISORIES... MO...NONE. KS...NONE. && $$ SHORT TERM...Terry LONG TERM...Terry AVIATION...Cramer FIRE WEATHER...Terry
Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
828 PM EDT Sun Apr 7 2019 .UPDATE... This afternoon has been a little quieter than yesterday with the showers and storms. Most of the storms were over Polk, Lee and Charlotte Counties with maximum winds reported around 20-30 knots. The radar is already quieting down and HRRR model guidance is keeping conditions quiet through the night. The big story of the day was the heat. Temperatures around the region topped out in the mid to upper 80`s with low 90`s in some areas, which is 8-10 degrees above average. Page Field at Fort Myers broke a record high today with 91 degrees recorded, which broke the old record of 89 degrees. Tomorrow will be a couple of degrees cooler, but still well above average. Forecast is on track with no changes needed. && .AVIATION... Overall VFR conditions are expected to hold through the period with some brief periods of BR restricting visibility to 4SM at KLAL between 09-15Z. Winds will be less than 05 knots overnight, then increasing south-southeast around 10 knots after 15Z, then turning onshore with a sea breeze after 21Z. No other aviation impacts expected. && .MARINE... High pressure will gradually give way to a system moving across the deep south during the first half of this week. Southeasterly winds gradually veer around to the south, southwest, and west Monday and Tuesday. A weak cold front will move through the waters on Wednesday, followed by high pressure building in from the north and northeast Thursday and Friday. Periods of showers and thunderstorms will be possible between Monday night and Tuesday night, with gradual improvement on Wednesday. && .Preliminary Point Temps/PoPs... TPA 72 84 72 80 / 10 20 30 60 FMY 71 87 71 84 / 0 20 30 60 GIF 70 88 70 83 / 0 40 40 60 SRQ 69 85 71 80 / 0 20 30 60 BKV 66 87 67 80 / 10 30 40 60 SPG 73 83 72 80 / 10 20 30 60 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...None. Gulf waters...None. && $$ UPDATE/AVIATION/MARINE...74/Wynn DECISION SUPPORT...25/Davis
...Update to aviation forecast discussion...

.SHORT TERM...(This evening through Monday) Issued at 321 PM CDT Sun Apr 7 2019 20Z water vapor imagery showed a shortwave over east central NEB moving into northwest MO. A pretty decent wind shift associated with a surface trough was also moving east through the mid MO river valley and east central KS. Surface temps were still able to warm into the lower and mid 70s behind the wind shift thanks to good insolation. An upper low was moving east along the TX and LA gulf coasts. Further west water vapor indicated a low amplitude synoptic pattern over the western U.S. with an upper low over the gulf of Alaska. For this afternoon, models continue to show limited low level convergence ahead of the surface trough this afternoon. Think this is why in spite of some surface based instability, models including the CAMs continue to show dry weather into this evening. Main concern overnight is the potential for some ground fog to develop. Weak surface ridging and clear skies appear to make a favorable set up for radiational cooling. But only the NAM shows significant saturation of the boundary layer. The RAP hints at some mixing of dry air at the top of the boundary layer to prevent saturation of the boundary layer. So I think widespread fog formation is unlikely. But I wouldn`t be surprised if there is some ground fog in the typical low lying areas around sunrise. So will mention some patchy fog mainly in the river valleys. Lows tonight are expected to fall into the mid 40s thanks to the radiational cooling. Forecast soundings show strong mixing of the boundary layer with good insolation for Monday. So highs in the upper 70s to around 80 looks on track. .LONG TERM...(Monday night through Sunday) Issued at 321 PM CDT Sun Apr 7 2019 Monday night through Wednesday morning looks to be dry as upper level ridging moves across the central plains ahead of the next upper wave. Temps should remain mild although highs Tuesday may not be as warm as Monday`s due to a weak boundary progged to move south into the forecast area. This may limit how deep the boundary layer mixes. So have highs from in the 70s. Am not to concerned about elevated precip early Wednesday morning as the models show the nose of the low level jet and 850 theta-e gradient north of the forecast area across NEB. But there are hints of high based instability near 500MB. The problem is there is quite a bit of dry air below this. So precip chances are to low to include in the forecast at this time. Wednesday afternoon and Wednesday night could be interesting from a severe weather standpoint. Models show dewpoints increasing into the mid 50s and possibly lower 60 degrees Wednesday afternoon with a dryline setting up across central KS. Wind fields are progged to be favorable for supercell storms if the inhibition from an elevated mixed layer can be overcome. And the 12Z GFS forecast soundings are showing a weaker cap in place by the late afternoon at SLN and CNK. However there remains a fair amount of uncertainty with the details as the models show varying tracks and strengths to the low pressure system. So we`ll need to keep an eye on how the models trend over the coming days. For now only have some small POPs across north central KS Wednesday afternoon with better chances for precip through the evening. There is more confidence in an increasing pressure gradient on Wednesday causing southerly winds to become windy. This potentially could create from fire weather concerns through the afternoon Wednesday. Late Wednesday night and Thursday look to be much cooler as models show a modified Canadian airmass advecting south behind the surface low. And depending on the track of the system, forecast soundings look cold enough that some snow could mix in with the rain across northern KS Thursday morning and again late Thursday night. At this point models are pretty light with any QPF that may develop across northern KS. So the impact from snow looks to be minor. Although a shift in the track of the system could bring the warp around moisture and colder air further south. The Wednesday/Thursday system is expected to be lifting out of the area by Friday leaving dry and cool weather in its wake. Another low pressure system is forecast to move through the plains next weekend. However the GFS wants to take this system south of the forecast area while the ECMWF and Canadian solutions bring it across the forecast area Saturday afternoon through Sunday morning. Have kept some low POPs in for the weekend until there is better agreement from the models. This would also keep temps on the cool side with highs in the 50s and around 60 with lows in the 30s. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 640 PM CDT Sun Apr 7 2019 Expect VFR conditions through most of the next 24 hours. After 10Z MON there could be some ground fog developing at KTOP and KMHK. Several of the higher resolution models are showing river valley fog developing. Potentially visibilities could drop under a mile but the river valley fog should mix out by 15Z MON. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Wolters LONG TERM...Wolters AVIATION...Gargan