Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/13/17

Area Forecast Discussion
National Weather Service Columbia SC
926 PM EDT Wed Apr 12 2017 .SYNOPSIS... A weak cold front in the forecast area tonight will be diffuse and just south of the area Thursday. High pressure moving into the Northeast States will ridge southward and into the forecast area Friday. The high will continue to dominate over the weekend as it slides southeastward to a position off the Southeast Coast Sunday. Another cold front approaching from the northwest will be near the area Monday supporting a chance of showers and thunderstorms. && .NEAR TERM /THROUGH THURSDAY/... The evening isolated showers and thunderstorms were hindered because of the dry air near the surface and in the mid levels. Nocturnal cooling has helped cause dissipation. The high- resolution models indicated increased low-level convergence in the piedmont late tonight associated with the interaction of the weak front and well inland protrusion of the sea breeze front, but additional development will probably not occur because of nocturnal cooling and lift ahead of the upper trough shifting east of the area. The HRRR did not indicate additional showers. The temperature forecast was on track and expect lows in the middle and upper 50s. Cooling and light wind may lead to fog toward sunrise but because of the dry near-surface layer expect any fog would be mainly confined near bodies of water and the few locations that had rain during the afternoon or evening. The SREF indicated low fog probabilities. The NAM and GFS MOS confined fog mainly to the river valley sites of AGS and OGB. Forecasted just patchy fog during the early morning hours. && .SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/... A weak cold front will drop south and east of the area Thursday morning, with veering winds through the day as high pressure builds from the Mid-Atlantic coast. As the low-level flow becomes more northeasterly late in the morning and during the afternoon, moisture will begin to advect into the region from the Atlantic. Weak surface convergence, mainly in the vicinity of the eastern Midlands and lower CSRA, could support isolated to perhaps scattered showers/thunderstorms from late morning through the afternoon in those areas. The northeasterly flow and added cloud cover during the day should keep temperatures from rising much above the upper 70s or lower 80s. Any lingering showers/thunderstorms into Thursday evening will quickly dissipate with the loss of daytime heating. Clearing skies, light winds and some left over low-level moisture could result in some patchy fog late Thursday night. Lows will be in the 50s across the area. For Friday and Friday night, strong upper-level ridging will build over the area from the northern Gulf Coast region as surface high pressure shifts into the western Atlantic. Strong subsidence and limited moisture will result in a abundant sunshine during the day and mainly clear skies at night. Highs will generally remain in the upper 70s to lower 80s, with nighttime lows in the 50s. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... The upper-level ridge will shift across the Florida Peninsula Saturday, with some weak short wave energy rounding the top of the ridge and passing across the area. Meanwhile, surface high pressure over the western Atlantic will allow for a southeasterly/onshore flow, which will not only increase low- level moisture but should allow the seabreeze to penetrate into the eastern Midlands. The GFS continues to indicate the potential for isolated showers across the eastern Midlands, but with little support from the other models. While an isolated shower seems possible, will take mention out of forecast as coverage will be very limited. Certainly expect an enhanced cumulus field however. Dry weather will prevail through Easter Sunday with deep layered ridging continuing to build into the region from the western Atlantic. The ridging breaks down Monday as a backdoor cold front approaches from the north, and eventually shifts into the area Monday night into Tuesday. The front then appears to lift back to the north as a warm front Wednesday. Given the presence of the front, most of the first half of next week appears to be unsettled, with a 20-40 percent chance of showers and thunderstorms in the forecast from Monday through Wednesday. Temperatures through the long-term period appear to remain slightly above normal. && .AVIATION /02Z THURSDAY THROUGH MONDAY/... VFR conditions expected through most of the TAF period. Visibility restrictions possible, mainly at AGS/OGB late tonight/early Thursday morning. A weakening surface front will move slowly into the forecast area tonight, and stall just to our south Thursday. With limited moisture to work with, there is only a slight chance of showers and thunderstorms at the TAF sites through early this evening, and again tomorrow afternoon. The upper-level trough will move east of the area late tonight, with clearing of high-level cloudiness expected. However, some low- to mid-level cloud cover could linger. Because of uncertainties with regard to cloud cover, and possibly some wind just behind the frontal boundary, will indicate fog mainly at the fog prone sites, AGS and OGB. EXTENDED AVIATION OUTLOOK...Late night/early morning fog/stratus possible through Saturday. && .CAE WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. && $$ SYNOPSIS...99 NEAR TERM...99 SHORT TERM...99 LONG TERM...99 AVIATION...99
Area Forecast Discussion
National Weather Service Dodge City KS
732 PM CDT Wed Apr 12 2017 ...UPDATE TO SYNOPSIS... .SYNOPSIS... Issued at 730 PM CDT Wed Apr 12 2017 WV imagery indicates a weak upper level shortwave trough of low pressure moving eastward across the Desert Southwest. Near the surface, a near stationary frontal boundary extends from southeast Colorado northeast into north central Kansas. A line of strong thunderstorms extends near and along the frontal boundary across much of western Kansas with some storms producing very heavy rainfall. && .SHORT TERM...(This evening through Thursday) Issued at 154 PM CDT Wed Apr 12 2017 There will be a chance for thunderstorms late this afternoon and early this evening along a surface boundary that will be located from east central Colorado border to north central Kansas. RAP and NAM both indicated an inverted V model sounding east of this boundary at 21z Wednesday and 00z Thursday with CAPE values in excess of 2000 j/kg. 0-6km shear was forecast to be around 30 knots across southwest Kansas and around 35 knots further north closer to the Nebraska border. Organized multicells appears to be the storm mode for early in this event. Also based on the models soundings the main hazard from developing thunderstorms late today and early this evening will be wind gusts up to 60 mph. Hail will also be possible with hail sized mainly one inch or less. Once developed these storms are expected to move easterly based on the 700mb to 300mb mean winds but as they exit the instability axis and with the loss of heating this evening these storms are expected to weaken. Areas north and west of Dodge City this late today will have the better chance for this scattered convection with the area favoring the strong winds being west of a Dighton to Ulysses line. Models remain in good agreement on a negatively tilted upper level trough lifting northeast across western Kansas on Thursday. As this system approaches late tonight and early Thursday the chance for rain showers will return. This will provide the best chance for precipitation across south central and portions of western Kansas. Main concern today is how far west the precipitation will spread during the day on Thursday. At this time am currently favoring keeping the better chances for precipitation east of the 700mb to 500mb deformation zone west northwest of the upper low/trough. Areas that do get this extended period of steadier rain on Thursday/Thursday night could easily receive anywhere from 1/2 to around 1 inch. .LONG TERM...(Thursday night through Wednesday) Issued at 154 PM CDT Wed Apr 12 2017 The ongoing precipitation across western Kansas will taper off Thursday night as the negatively tilted upper level trough lifts northeast into eastern Nebraska. A surface boundary, extending west to northeast across western Kansas at 00z Friday, will lift northeast as a warm front Thursday night which will shift the winds from the southeast to a more southerly direction. Low clouds along with some fog is expected Thursday night but the combination of a more southerly wind and low level winds speeds increasing late night confidence is not high for dense fog developing. The area more favorable for fog and possibly even some drizzle Friday morning will be in north central Kansas based on the moisture profiles from the NAM. Gusty south to southeast winds will develop early Friday as surface pressure falls along the lee of the Rockies as another upper level trough approaches from the west. Based on the moisture return and 0-1km moisture convergence along a surface boundary there may be a few isolated late day/evening thunderstorms near the Colorado border but given the warm mid temperatures around the 700mb level the probability appears very low. Temperatures on Friday should warm up nicely given the expected mixing depth and mix down temperatures at that level. Highs 80 to 85 still looks on track...could even be a little warmer in far western Kansas. A better chance for convection will occur on Saturday as a cold front crosses western Kansas. A few strong or even severe thunderstorms will be possible late day along this frontal boundary as it crosses south central Kansas late Saturday afternoon/early Saturday evening. Cooler, more seasonal, temperatures will return to western Kansas on Sunday as a surface ridge axis crosses the Central Plains and a cold front stalls out across the Texas Panhandle and Oklahoma. What little sun that does develop early Sunday will give way to increase clouds and possibly even some precipitation will develop late day as moisture and lift improves north of the surface boundary in northern Oklahoma. Based on the moisture and isentropic lift in the 295 to 305 levels along with the 850mb warm air advection the area more favorable for this precipitation will be south of the Arkansas river from late Sunday through early Monday. Current Highs forecast Sunday in the 65 to 70 degree range may be a little too warm given the expected Cloud cover and probability of precipitation. A warming trend will begin early next week as a warm front lifts north across southwest Kansas. Confidence is not high on how quickly the cooler air will erode on Monday so although did not stray far from guidance the highs of around 75 on Monday may be a little to warm if the warm front is slowly to lift north. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 617 PM CDT Wed Apr 12 2017 Scattered thunderstorms will move eastward across central and northern portions of southwest Kansas through late this evening, potentially affecting KHYS, KGCK, and possibly KDDC with brief MVFR vsbys due to heavy rainfall. Otherwise, VFR conditions are expected to prevail at all TAF sites through late Thursday morning. Although a surface low will remain anchored across southeast Colorado tonight, southerly winds 20 to 30kt will subside through late this evening with the loss of daytime heating. Southerly winds are then expected to increase again toward early Thursday afternoon as the surface low strengthens. && .PRELIMINARY POINT TEMPS/POPS... DDC 53 67 56 79 / 30 60 50 10 GCK 51 67 53 82 / 40 50 30 10 EHA 50 70 53 82 / 20 40 20 10 LBL 54 68 54 81 / 30 60 30 10 HYS 51 69 56 78 / 60 50 60 10 P28 56 70 58 77 / 30 70 70 20 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...JJohnson SHORT TERM...Burgert LONG TERM...Burgert AVIATION...JJohnson
Area Forecast Discussion...CORRECTED
National Weather Service Quad Cities IA IL
648 PM CDT Wed Apr 12 2017 ...AVIATION UPDATE... .SYNOPSIS... ISSUED AT 404 PM CDT Wed Apr 12 2017 GOES IR satellite imagery showed mainly clear skies through much of the day give way to a mid-level overcast now entering eastern Iowa. The mid-level clouds will overspread all of E Iowa/NW Illinois and NE Missouri through the late afternoon and early evening. The abundant sunshine caused sfc temps to rise into the 60s, and combined with light winds, led to a very nice day. An area of convection, with cloud tops colder than -60 C, was noted over extreme NE Kansas. This region of thunderstorms was producing cloud-to-ground lightning. Further north into Nebraska, an area of convection has weakened to just showers within the last hour. The shortwave trough responsible for these showers and thunderstorms will impact the local region tonight. && .SHORT TERM...(This Evening through Thursday) ISSUED AT 404 PM CDT Wed Apr 12 2017 This Evening and Tonight: A low amplitude mid-level wave will be strong enough to bring a round of showers and thunderstorms through the CWA tonight into early Thursday morning. Recent SPC mesoanalysis had a 850mb low- level jet situated over Kansas and E Nebraska, pumping moisture northeastward. Models move this feature to the ENE tonight, placing the area of 925-850mb WAA and convergence over the northern two-thirds of the CWA. The HRRR has trended slightly further south with the heaviest rain which will occur toward the southern edge of the complex of showers - in the overlap zone of better instability but still sufficient forcing. Expect a widespread 0.25 to 0.50 inches, and likely a focused corridor of heavier amounts up to 0.75-1.00 inches. The one exception is probably the far south/southwest sections of the CWA. Here rainfall may be under 0.10 inches. Marginal shear and instability will preclude any threat for severe weather. Thursday: Showers and embedded thunderstorms are forecast to decrease in coverage as the low-level jet wanes. There is a low chance for isolated showers and thunderstorms redeveloping near a sfc boundary during the afternoon, mainly south of I-80. The main story will be the large north-to-south temp gradient from the upper 50s far north to the mid 70s far south. It could potentially be colder across the north half of the CWA in a NE sfc flow under overcast skies, but didn`t want to trend any colder due to some model disagreement. .LONG TERM...(Thursday Night through Wednesday) ISSUED AT 404 PM CDT Wed Apr 12 2017 Thursday Night through Saturday Night: Next shortwave trough to impact the Midwest. Low-level pressure fields show a warm front lifting through the area on Friday, followed by a cold front on Saturday. Expect periodic chances for showers and thunderstorms. One concern is that a moist air mass may result in areas of heavy rainfall. NAEFS PWATs exceeding 1.25 inches are 2-2.5 standard deviations above average for the middle of April. However, the good news is the warm front is not forecast to stall over the CWA on Friday. Also, the rain on Saturday will be associated with a transient cold front, decreasing the threat for excessive rainfall. At this time, deep layer shear is not favorable for severe weather. Sunday and Monday: High pressure and post-frontal air mass moves into the Midwest - so drying out and pleasant for the end of the weekend/early next week. Tuesday and Wednesday: Another trough approaches the area. Rounds of showers and storms are likely, but may hold off until Tuesday night. Rises on area rivers could become a concern during or after this round of rain. && .AVIATION...(For the 00Z TAFS through 00Z Thursday Evening) ISSUED AT 640 PM CDT Wed Apr 12 2017 Scattered showers ahead of an upper level disturbance may produce sprinkles at CID, BRL and MLI in the evening. Overnight, another round of showers is likely as a weak system sets up a frontal boundary over southern Iowa. There is a low potential for thunderstorms, which is no longer included in the terminal forecasts. Conditions are expected to deteriorate to IFR due to lowering ceilings as low clouds setup along and north of the surface front. Ceilings are likely to lift to MVFR during the day Thursday, but confidence is low in the timing. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ ...corrected for formatting... SYNOPSIS...Uttech SHORT TERM...Uttech LONG TERM...Uttech AVIATION...Sheets
Area Forecast Discussion
National Weather Service Sioux Falls SD
1037 PM CDT Wed Apr 12 2017 .SHORT TERM...(This evening through Thursday) Issued at 338 PM CDT Wed Apr 12 2017 Afternoon water vapor imagery shows strong signature of jet streak diving into eastern SD this afternoon, with main lift currently shifting into far northeastern CWA near KMML. At the surface, weak low pressure centered over northern Nebraska with warm front southeast toward I-80. Curiosity of the day has been the persistent area of smoke which has streamed northward from eastern Kansas, and has been caught up in convergence zone over heart of the CWA from KYKN to KFSD and east into far northwest Iowa. Even with rainfall passing through, the smoke persisted with the strengthening of the inversion, which finally should start to mix and advect out as flow turns more northeast at low levels. With synoptic scale subsidence in wake of the passage of PV maximum pushing into southwest MN, have a little doubt that more mesoscale lift forcing in the lower- to mid-level warm advection across areas near/east of I-29 very late afternoon into early evening will be strong enough to overcome the larger scale subsidence component. Presence of convection between I-80 and I-70 is not a positive factor either, as will help to veer low-level winds as well. HRRR and especially NAM have been quite bullish with redevelopment of showers/isolated T across northwest Iowa during the early evening, and actually showing a backing of this warm advection zone further westward. Will maintain some modest chance PoPs over mainly northwest Iowa into southwest MN through early evening, at least until lingering low-level jet veers even further eastward. Main issue heading forth after the ending of precipitation this evening will be potential for stratus/fog with persistent east/northeast surface flow through Thursday. At this point, a fairly strong consensus for stratus to develop across parts of southern MN and northern IA during the later evening, then spread west and southwest across much of the area through Thursday morning. Not sure how much would be fog vs. stratus, and have kept fog at more patchy levels compared to a greater coverage of lower clouds, which should reach a maximum sometime in the mid morning. While models are fairly insistent that clouds will fully mix out by early afternoon on Thursday, am more confident of this occurrence across areas west of I-29 downstream of ridge axis, with some areas perhaps lingering into a broken ceiling state much longer toward southwest MN and northwest IA. There should at least be some sunshine in all areas during the afternoon, and will help temperatures reach near 60 in cloudier eastern zones, and perhaps mid to upper 60s in the Missouri River valley. .LONG TERM...(Thursday night through Wednesday) Issued at 338 PM CDT Wed Apr 12 2017 Models in better agreement today bringing a compact shortwave through the CWA early Friday. Instability continues to look meager with this system as it moves through, but will continue to indicate a minimal thunderstorm risk. Subsidence behind this wave should keep things at bay in the afternoon and early evening. With the LLJ intensifying a bit after midnight, still anticipated renewed convection along the stalled boundary early Saturday morning. Still a questionable risk for a few strong storms early Saturday. Drier air sweeping southeast should push the risk for convection into Iowa by the afternoon hours. A very nice day is in store for Sunday, with another cold front arriving Monday morning. A very active pattern continues into next week, with a progressive wave moving into the Northern Plains quickly by Tuesday morning. Return flow and broad warm advection ahead of this wave could spark an increasing elevated shower risk late Monday into Monday night, with higher thunderstorms risks overnight into Tuesday morning as a front sweeps through. Some considerable differences remain in extended range guidance, more in the specifics than the general pattern, so timing of rain chances is likely to change. && .AVIATION...(For the 06Z TAFS through 06Z Thursday night) Issued at 1022 PM CDT Wed Apr 12 2017 Main aviation concern overnight will be impending stratus and fog. Northeasterly flow will cause stratus and fog currently present across southwest Minnesota to spread across southeast South Dakota and northwest Iowa. FSD and SUX will likely be impacted. Left visibility or ceiling restrictions out of the HON TAF due to lower confidence in stratus or fog reaching that terminal. Conditions should recover by early afternoon Thursday. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. IA...None. NE...None. && $$ SHORT TERM...Chapman LONG TERM...Dux AVIATION...Ferguson/JM
Area Forecast Discussion
National Weather Service Goodland KS
849 PM MDT Wed Apr 12 2017 .UPDATE... Issued at 846 PM MDT Wed Apr 12 2017 Just completed an update. Per new model output and collaboration with my neighbors, increased cloud cover over the western portion of the area to account for the expected overnight stratus. Per latest observational trends, made adjustments to the overnight temperatures. Moisture, a little stronger winds, and cloud cover will affect the southeast portion of the area first so increased the lows there. Lighter winds and less cloud cover for longer will make for cooler lows over the northwest half, and lowered those temperatures. Current pops and development of overnight fog look good and made little if any adjustments. && .SHORT TERM...(This afternoon through Thursday) Issued at 203 PM MDT Wed Apr 12 2017 Two distinct mid level shortwave troughs are splitting around our CWA. A weaker ripple within the mid level flow may be moving over our CWA based on RAP analysis (though this isn`t showing up in WV imagery). WV shows dry/subsident air mass just northwest spreading south and east. At the surface a weak cold front has pushed into the far northwest part of our CWA, with a prefrontal trough axis near Tribune extending just southeast of Hill City. A CU field has developed along the area of covergence near this surface trough in our southeast (mainly outside of our CWA). This afternoon-evening: Latest mesoanalysis shows axis of ML cape in the 10-1500 J/KG range along and south east of surface trough in our SE CWA where CIN is beginning to weaken. High resolution models show thunderstorm activity developing along this covergence zone/axis of instability. Tendency will be for this activity to remain just southeast of our CWA, but I can`t rule out this activity developing just within our CWA. Better instability and shear would be east- southeast, but there may be enough for an isolated/organized cell. Based on near term convective allowing models this activity should transition southeast of our CWA with mean flow and should end early this evening. Late tonight-Thursday morning: Low level flow shifts to the southeast and will be responsible for increasing BL moisture and a long fetch of upslope. BL winds may increase enough to limit dense fog potential, however stratus and light fog are still possible. This also complicates lows, and I could see a situation where parts of our CWA do not drop out of the 50s if cloud cover fills in quick enough this evening. Thursday: A stronger negatively tilted mid level trough swings over our CWA. Model soundings show PWATS just under 1" and strong forcing combined with this moist air mass should support increasing shower coverage across our east and the possibility for moderate rainfall amounts Thursday afternoon. Track could limit potential with dry slot/subsident region across our west. There should be enough instability for embedded thunderstorms, maybe even a stronger storm. I`m not particularly confident as in this as models show a fairly high spread (possibly dependent on clearing skies. Best instability on NAM is actually in subsident region. Models may be running high for daytime temps if shower/thunderstorm coverage is better in the east as consensus seems to indicate, so I trended highs down slightly during this update. .LONG TERM...(Thursday night through Wednesday) Issued at 201 PM MDT Wed Apr 12 2017 The pattern remains active throughout the long term with multiple disturbances passing near the area. Temperatures look to stay near to above normal. The first wave continues to move across the area Thursday night, exiting Friday morning. With some instability and increasing moisture, showers and thunderstorms are possible, mainly east of the Colorado border. Precipitation chances shift east of the region Friday morning. However, another disturbance enters the High Plains from the west and chances for showers and thunderstorms persist during the afternoon and evening. A few strong to severe thunderstorms could develop during this time, with the main threats as large hail and damaging winds. Dry weather is currently anticipated for most of the weekend. A cold front pushes through on Saturday and southwesterly flow aloft turns zonal. Precipitation chances return Sunday night into Monday when a shortwave traverses the region. Unsettled weather continues into next week as periodic shortwaves move through the flow, generating on and off chances for showers and thunderstorms. Will need to wait for better agreement among guidance to nail down timing and locations impacted. Temperatures peak at the start of the period with highs mainly in the low 80s. A cold front pushes through on Saturday dropping temperatures into the upper 60s/70s for the rest of the long term. Lows will generally be in the 40s and 50s. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 522 PM MDT Wed Apr 12 2017 VFR conditions prevail through the first portion of the TAF period for both sites. Winds will remain in the 5 to 8 kt range through much of the night and into Thurs morning. Winds will gradually shift easterly to southeasterly tonight, ushering in better moisture values as we head into Thursday morning. This will allow for potential fog and stratus development through the early morning hours at both KGLD and KMCK. IFR to LIFR conditions could become a possibility at KMCK with MVFR to IFR possible at KGLD around or just after 12Z. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...BULLER SHORT TERM...DR LONG TERM...JBH AVIATION...TL
Area Forecast Discussion
National Weather Service Jacksonville FL
903 PM EDT Wed Apr 12 2017 .UPDATE... Tonight...Weak High pressure ridge will linger at the surface while a weakening upper level trof will cross the region and produce a period of upper level clouds through the night but no precip is expected. This trof axis, along with its clouds will keep atmosphere mixed a bit and lessen the risk of fog towards the morning hours and have removed the patchy fog from the current forecast as latest HRRR forecast runs have removed any reductions in visibilities across inland SE GA late tonight. Lows still generally in the 50s inland and near 60 along the coast. Thursday...High pressure will re-build just NE of the region over the Carolinas and will send a NE surge of winds into the region along with some Scattered to Broken Strato-Cu field off the Atlc Ocean that will push across coastal areas in the morning and spread across the rest of the inland areas with normal diurnal heating. NE winds will be closer to 15G25 mph at the coast and 10-15G20 mph further inland with this renewed surge. Models still show this new airmass too dry to support much in the way of any shower activity, but it may shave a couple of degrees off Max Temps compared to this afternoon with mid/upper 70s along the coast and lower 80s further inland. && .AVIATION... Still another mainly VFR forecast. Overnight expect just mainly a few high clouds with trof axis aloft, although strato-cu offshore will start to come closer to the coast by morning. The NE surge of winds is expected to push SCT-BKN strato-cu onshore during the morning hours after 12z, and for now have advertised 3500 ft CIGS but could be a brief MVFR CIG at the coast during the morning hours. NE winds will increase to 12-14G20kts by the late morning or early afternoon hours. && .MARINE... ENE winds at 10-15 knots will shift NE and increase slightly with surge on Thu with some 15-20 knot speeds over the offshore waters and SCEC headlines will be possible. Seas 2-4 ft tonight will increase to 3-5 ft tomorrow. Rip Currents: Moderate risk in the continuing onshore flow. && .PRELIMINARY POINT TEMPS/POPS... AMG 54 83 57 82 / 0 0 0 0 SSI 62 75 63 74 / 0 0 0 10 JAX 56 79 60 79 / 0 10 0 20 SGJ 61 76 64 76 / 0 0 0 30 GNV 55 81 57 82 / 0 0 0 20 OCF 56 82 57 83 / 0 0 0 10 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AM...None. && $$ Hess/Nelson/Walker
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
624 PM CDT Wed Apr 12 2017 .SHORT TERM... 225 PM CDT Through Thursday... High pressure will continue east as will the thin layer of cirrus over much of the region. Winds will turn east across the forecast area and increase to 10-15 MPH this evening. Cloud cover also thickens ahead of the next system. An upper level disturbance over the northern plains will move over the region Thursday. Showers and isolated to scattered embedded thunderstorms are expected early Thursday morning. Guidance still differs widely on how quickly precip will spread east. The GFS, ECMWF, and a couple of hi-res models have the quicker solutions that bring precip through at least the I-55 corridor by 7AM CDT. Slower solutions like the NAM and RAP only have the precip along and west of a McHenry to Peru, IL line by 7AM CDT. I`m thinking it will take time for the column to saturate tomorrow, so went with a slower solution than the GFS and ECMWF, but still faster than the NAM and RAP. While my confidence is high in showers, it is medium in exact timing. I also have medium confidence in my thunderstorm forecast. We`ll be working with minimal values of elevated CAPE so I chose to keep a slight chance across the forecast area through Thursday morning. Precip shifts south and festers along a stationary boundary south of I-80. Models have CAPE increasing near the front, but soundings still only feature elevated CAPE so I kept thunder as a slight chance. While lows tonight will be about 10 degrees warmer than last night away from the lake, cloud cover will limit warming tomorrow. Have high temps ranging from the mid 50s along the IL/WI state line to around 70 across the far southern portions of the forecast area. Onshore flow will once again keep lakeside temps in the upper 40s. JEE && .LONG TERM... 225 PM CDT Thursday night through Wednesday... The period will begin Thursday night with low clouds and possibly some showers across the area as a surface frontal boundary stalls out over central Illinois and Indiana. Some modest isentropic ascent is forecast to continue Thursday night along and north of this frontal boundary, and this may continue to result in some rain showers across portions of the area into Friday morning. However, this frontal boundary is expected to shift back northward across the area later Friday and Friday evening in response to a decent mid-level short wave shifting over the Upper Mississippi Valley and Western Great Lakes region. This feature is likely to drive a better chance of showers and thunderstorms over the area into Friday evening. Temperatures during the day will again be much cooler along the lakefront in Illinois due to the onshore flow, but temperatures may end up warming during the evening as the surface warm front shifts the winds offshore. Once the warm front shifts north of the area Friday night, conditions look to become quiet warm and breezy across the region in the warm sector Saturday. Temperatures at 925 MB are progged to reach near 20 C, which could yield temperatures right around 80 degrees across portions of the area. Gusty southwest winds up around 30 MPH during the day will also likely prevent lake breeze development. Therefore, these very warm conditions are likely to reach the lake front areas. While conditions should be dry across the area Saturday, another round of showers and thunderstorms is likely to impact the region Saturday night into early Sunday morning, as a storm system tracking over the Upper Midwest, drives a cold front across the area. Cooler weather is likely to set up in the wake of this front for early next week. This will especially be the case for areas near Lake Michigan, where the presence of high pressure over the Great Lakes region will favor persistent onshore flow early next week. The next chance of showers and thunderstorms looks to be late Tuesday and Tuesday night, when another storm system looks to impact the central portion of the country. KJB && .AVIATION... For the 00Z TAFs... 624 pm...Forecast concerns include showers developing by sunrise Thursday morning and cigs lowering into ifr Thursday morning and possibly to lifr by Thursday evening. Showers will spread across northern IL after midnight and short term/hi res guidance has been speeding up the arrival time... possibly in the 07z-08z time period at rfd and by 11z at the Chicago terminals but further tweaks to timing can be expected with later forecasts as trends emerge. These showers and maybe a more prolonged period of rain will continue through late Thursday morning...tapering off to drizzle in the afternoon. Limited instability aloft should keep thunder chances isolated and also mainly south of the no mention with this forecast. Mid clouds this evening will gradually lower through the night and once precip arrives...mvfr cigs will develop. Only medium confidence on how fast these mvfr cigs will lower but eventually... they should lower into ifr by mid/late Thursday morning with ifr cigs expected Thursday afternoon. Guidance suggests cigs could lower further into lifr by Thursday evening... but low confidence on cig trends that far out with this forecast. Winds will remain generally easterly through the period around 10kts. cms && .MARINE... 241 PM CDT Easterly winds are expected to continue over much of Lake Michigan through Friday as surface high pressure remains dominate over the Upper Great Lakes and southern Canada. Wind speeds of 15 to 20 KT are expected over southern Lake Michigan late tonight into Thursday as the surface gradient tightens in response to a weather disturbance moving across the area. These winds are likely to result in waves building to 2 to 5 feet in the Illinois near shore waters for Thursday. At the present, this appears to be just below small craft advisory criteria, so we will hold off on a headline. A warm front is expected to shift northward over the lake Friday night into Saturday. This will allow the winds to shift south- southwesterly for Saturday. Given the strong gusty offshore winds over Illinois and Indiana, wind speeds up to 30 KT may occur over the southern Lake Michigan near shore waters. However, lighter winds are expected over the open waters of the lake due to stable conditions. A cold front is then expected to shift over the lake Saturday night into Sunday. A period of showers and thunderstorms is likely to accompany this front, followed by a westerly wind shift. KJB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...None. IN...None. LM...None. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion...UPDATED
National Weather Service Memphis TN
933 PM CDT Wed Apr 12 2017 .UPDATE... Other than scattered cirrus, skies were clear across the Midsouth at midevening. With light winds and dewpoints in the 40s and 50s, temps had cooled a little quicker than earlier forecast. Expect temps to level off a bit during the overnight. In earlier updates, have adjusted hourly trends and dropped overnight lows slightly. HRRR and SREF guidance suggest limited potential for overnight fog, but could still see some reduced visibilities in river valleys and near other bodies of water. PWB && .PREV DISCUSSION... /issued 652 PM CDT Wed Apr 12 2017/ UPDATE... Updated for 00z Aviation Discussion. DISCUSSION... /issued 311 PM CDT Wed Apr 12 2017/ Skies remain mostly sunny across much of the forecast area this afternoon with temperatures mainly in the 70s. High pressure is over lower Michigan this afternoon. The high will keep dry weather and mild temperatures over the region tonight with lows Thursday morning from the mid 50s to around 60 degrees. Thursday will be another nice day with dry weather above normal temperatures with highs in the upper 70s to lower 80s. Thursday night will be warm and dry with lows Friday morning in the upper 50s to lower 60s. Friday will see some isolated thunderstorms possible in the afternoon hours. Temperatures will remain warm on Friday with highs in the lower 80s. Dry weather will return for Friday night and Saturday as temperatures remain above normal. By Saturday night, a cold front will move across the central plains and the Mid-Mississippi valley. Thunderstorms are expected to form ahead of the front with some of this activity possibly moving into northern sections of the forecast area. As the front moves closer to the region on Sunday, there will be a better chance of thunderstorms over the forecast area. The cold front will move into the forecast area Sunday night and into north Mississippi Monday morning. More thunderstorms are expected for both periods. The cold front stalls out over north Mississippi for Monday night and Tuesday. This will mean there will still be a chance of thunderstorms for both periods. By Tuesday night, the front will start to lift slowly north as a warm front and will be just east of the forecast area by next Wednesday. This will mean there will still be a chance of thunderstorms for both Tuesday night and Wednesday. Temperatures will remain a few degrees above normal for the period from Monday through next Wednesday. ARS && .AVIATION... 00Z TAF set VFR conditions expected at TAF sites through the period. Light winds will become south winds around 5 kts on Thursday. CJC && .MEG WATCHES/WARNINGS/ADVISORIES... AR...None. MO...None. MS...None. TN...None. && $$
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
1051 PM CDT Wed Apr 12 2017 .SHORT TERM...(This evening through Thursday) Issued at 340 PM CDT Wed Apr 12 2017 The short term concern is the overall extent of light rain showers tonight into Thursday morning. Then the cloud/temperature trends into Thursday. Latest radar loop showing banded area of rain lifting east/northeast across the cwa. It matches well with the isentropic forecast using 295K. We do like the latest HRRR handling the rain into the evening. Looks similar to the overall 12z GFS trend. We will lift area with its categorical/likely PoP east across the region mainly through 06z Thu, then trend dry but remaining cloudy. Rainfall amounts should remain generally one quarter inch or less as it moves through. Clouds will likely linger into much of Thursday after some more fog in the morning. Lower level boundary layer flow remains moist under the influence of the surface ridge. Temperatures should remain in the 50s much of the area once again...with a 60 degree reading out west if clouds break up enough. .LONG TERM...(Thursday night through Wednesday) Issued at 340 PM CDT Wed Apr 12 2017 Confidence remains high that rain will fall at most locations on Friday into Friday night. It also appears that precip will linger through Saturday. Another storm system will bring showers and possibly some thunderstorms across Minnesota and Wisconsin on Tuesday, but there is considerable disagreement between the models. Did not make any changes to the temperatures but did increase clouds and winds on Sunday as it appears gusts near 30 mph are possible during the afternoon with deep mixing and cold air advection. Forecast models are in remarkable agreement with an upper level wave developing over the Texas panhandle and lifting up through the Midwest. This will lead to an area of showers and thunderstorms that will overspread the region on Friday. GEFS has over 90% probability of measurable precip, and no operational model is dry. Therefore felt obligated to increase precip chances for late Friday despite the timing and location difference with the heaviest QPF. Southwest flow continues which support rising air and prolonged period for rain as there is some low level convergence ahead of a passing cold front. Forecast soundings show very little MUCAPE, so do still have mention of thunder, but not anticipating any severe weather, which agrees with the SPC outlook. Looking ahead, another wave will bring precip across the region on Tuesday. The GFS 12.12 goes crazy and develops a deep surface cyclone, while the ECMWF and GEM are more progressive with the wave. All the models do support increased chances for showers and possible some thunderstorms, with snow to the north of the low track. && .AVIATION...(For the 06Z TAFS through 06Z Thursday night) Issued at 1051 PM CDT Wed Apr 12 2017 The main concern overnight deals with the timing on low MVFR/IFR ceilings and visibilities in the wake of the light rain this evening. Confidence is highest for the lowest conditions at KAXN, KRWF and KSTC, which are near the back edge of the clouds as well as in conjunction with high levels of low level moisture. Further east, VFR clouds are more extensive with low MVFR/IFR ceilings developing late in the night. The visibility may not lower past MVFR due to increasing wind associated with an inverted surface trough developing across the area. The wind could also impact how low visibilities go for the western terminals as well. Confidence is decreasing on ceilings lifting to VFR Thursday afternoon across WI and dropped them back to 025-030. Mainly east winds less than 10 knots. KMSP...MVFR ceilings and visibilities developing shortly after TAF issuance with a period of ceilings below 010 still expected around daybreak. Confidence is decreasing some on ceilings becoming VFR Thursday afternoon but left them at BKN035 at this point. /OUTLOOK FOR KMSP/ Fri...AM VFR. PM MVFR SHRA/TSRA. Wind SE 10-15 kts. Sat...MVFR SHRA/TSRA likely. Wind SW 5 kts becoming NW. Sun...VFR. Wind W 10-20 kts. && .MPX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. && $$ SHORT TERM...DWE LONG TERM...JRB AVIATION...RAH
Area Forecast Discussion
National Weather Service Pendleton OR
756 PM PDT Wed Apr 12 2017 .SHORT TERM...Tonight and Thursday...A moist southwest flow over the forecast area this evening with widespread rain. This is all occurring ahead of an approaching cold front that will sweep across the forecast area late overnight and exit Thursday morning. Precipitation will decrease west to east behind the cold front with some increase of westerly winds. A cooler unstable airmass will move in behind the cold front which will lead to instability showers Thursday afternoon with the possibility of some thunderstorms producing small hail. && .PREV DISCUSSION... /issued 211 PM PDT Wed Apr 12 2017/ SHORT TERM...A low pressure system over the e pac will continue to pump moisture into the two state area overnight. 5h/mb divergence aloft should further enhance the shower activity that is expected to expand in coverage and intensity into this evening and some rivers may approach bankfull. A cool front is forecast to race across the region tonight with some drier air to follow on a westerly downslope wind over portions of the basin by Thursday morning. Some rap around moisture will move into the region that could become convective and produce an isold tsra mainly over the eastern half of the region Thursday afternoon. Meanwhile another wave of moisture will increase pops over our southern zones into Thursday aftn/night. A further challenge will be lowering snow levels and a few inches of snow is possible above 3k feet into Friday morning especially over the blue/wallowa mtns. The bulk of the moisture should drift away of the region and a weak ridge of high pressure should build into the two state area Friday night. LONG TERM...Saturday through Wednesday. Mainly dry conditions with seasonal temperatures are expected Saturday and most of Sunday as a ridge of high pressure moves through the region. A low pressure system is expected to open and move across from south to north over the area Sunday night through Monday with another round of showers. A large area of low pressure will remain off the west coast through the mid part of next week with several disturbances rotating around the trough and will keep the showery conditions through much of next week. Temperatures will be below normal through the weekend and then moderate to near normal through the week. 93 AVIATION...00z Tafs. Mainly VFR conditions will continue through Thursday with several rounds of showers moving through as a low pressure area drifts north along the Washington/Oregon coast. Heavier showers will cause periods of below VFR conditions at KYKM, KDLS, KRDM and KBDN. Winds will be 10-15 kts. 93 && .PRELIMINARY POINT TEMPS/POPS... PDT 45 57 38 52 / 100 40 40 30 ALW 47 59 41 54 / 100 40 40 40 PSC 46 61 41 58 / 100 20 20 20 YKM 44 60 36 57 / 100 20 20 20 HRI 45 60 40 57 / 100 20 20 20 ELN 41 55 36 52 / 100 20 20 20 RDM 35 51 27 49 / 90 50 40 20 LGD 44 53 34 47 / 100 70 80 50 GCD 41 51 32 46 / 100 40 60 40 DLS 45 58 41 56 / 100 20 30 20 && .PDT WATCHES/WARNINGS/ADVISORIES... OR...None. WA...None. && $$ 91/91/91
Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
607 PM EDT Wed Apr 12 2017 .UPDATE (Overnight and Thursday)... 23Z water vapor and H4 RAP analysis shows a well-defined mid/upper level shortwave evolving slowly eastward along the northeast Gulf Coast this evening. Shortwave is a fairly potent spin via NWP analysis...but does not extend any lower than about 700mb...virtually undetectable at 850mb. This impulse, despite its appearance from a abs vort/PV perspective, is highly lacking in moisture and not translating much influence into surface based sensible weather. Seeing a few thunderstorms under the cooler core aloft toward the western FL panhandle/southern Alabama, but these should diminish with the setting of the sun and loss of diurnal heating. Closer to home...have seen a few speed convergence showers over far south FL the past few hours within a zone of slightly deeper moisture along and south of Lake Okeechobee, but this activity has been struggling to reach the I-75 corridor. Will likely still see a few brief showers in Lee/Charlotte/Sarasota/Desoto/Highlands counties in the next few hours...but this activity should be widely scattered and brief for any locations lucky enough to see a showers. Keeping overall rain chances on the low side and will end all PoPs after 03Z. During the overnight and early portion of Thursday...shortwave aloft mentioned above will slowly pivot to the southeast and over the FL peninsula while beginning to shear out. Therefore, do not expect much if any impact form this energy on our forecast. By Thursday afternoon...the sheared out trough axis will be to our east, followed by the arrival of a swath of NVA and further mid- level drying. With this in mind...the potential for any late day showers to the south of the I-4 corridor is even lower on Thursday. North of the I-4 corridor the rain chances are about zero. Temperatures the next 24 hours will be seasonable. Winds shift back offshore at the coast this evening and remain from the east to northeast through the overnight/morning hours of Thursday. Sea-breeze will struggle to move onshore again on Thursday...with a wind shift to the northwest in the afternoon limited to areas within a couple miles of the coast. && .AVIATION (12/23Z THROUGH 14/00Z)... Prevailing VFR conditions with no significant aviation concerns expected through the duration of the TAF period. SCT-BKN clouds with bases between 5-8KFT this evening may produce a brief shower for KPGD/KFMY/KRSW...but not restrictions expected. Where winds have shifted onshore they will shift back to the east by 01-03Z and remain from the E/NE through Thursday morning. Sea-breeze will again make limited inland penetration Thursday afternoon, with KTPA/KPIE/KSRQ seeing best potential for a brief winds shift to an onshore direction after 19Z. && .Prev Discussion... /issued 237 PM EDT Wed Apr 12 2017/ SHORT TERM (Tonight - Thursday)... A short wave trough over the northern Florida peninsula tonight will dampen out as it drifts southeast along the Florida east coast on Thursday and into the Bahamas Thursday night as upper level ridging over the central Gulf re-builds slowly east in its wake. At the surface high pressure over the Atlantic offshore the mid Atlantic coast will maintain a northeast to easterly wind flow over the region through the period. For tonight any ongoing showers across central and southern locations and the adjacent Gulf waters associated with a westward moving inverted trough will end or shift west over the Gulf waters after sunset with mainly dry conditions expected overnight. Temperatures tonight will be near seasonal levels with lows in the upper 50s north, and lower to mid 60s central and south. On Thursday upper level ridging over the central Gulf will build and expand slowly eastward during the day as the aforementioned short wave trough dampens out along the Florida east coast and over the Bahamas. Drier air (Pw`s less than 1 inch) advecting in from the Atlantic during the day within the modest northeast to easterly wind flow will support a warm and mainly dry day across the forecast area with ample sunshine expected. The exception to this will be across southwest Florida where slightly higher moisture combined with the weak sea breeze may support a few showers late in the afternoon where a low 20 percent pop mention will be advertised. Temperatures on Thursday will continue to run a few degrees above normal with highs climbing to around 80 to the lower 80s along the coast, and mid 80s inland. LONG TERM (Thursday Night - Wednesday)... High pressure at the surface will be building into the region from the NE as upper ridging over the Gulf shifts east over the state through Saturday. The upper ridge will then become more zonal for Sunday through Wednesday as the surface high settles south over the west Atlantic ridging back across the state. Conditions will remain mostly dry, with a few afternoon showers becoming possible for late in the period Tuesday and Wednesday afternoons. Winds will be generally E/NE through the period with some evening surges possible. Temperatures will remain above normal through the period. MARINE... Surface high pressure offshore the mid Atlantic coast will get reinforced by another ridge of high pressure moving offshore the northeastern states late in the week and during the upcoming weekend. The high will maintain an elevated northeast to easterly wind flow (10 to 15 knots near shore and around 15 knots offshore) over the Gulf waters through the period with cautionary wind surges (in the 15 to 20 knot range) likely during the evening and overnight time frames. FIRE WEATHER... Some pockets of humidity values below 35 percent will be possible over interior sections of the forecast area during the next few days, otherwise sufficient low level moisture should keep humidity values above critical levels through the end of the week and into the upcoming weekend with no Red Flag conditions expected. && .Preliminary Point Temps/PoPs... TPA 65 82 63 84 / 10 0 0 0 FMY 65 83 63 85 / 30 20 10 0 GIF 62 82 61 84 / 10 0 0 0 SRQ 64 82 62 84 / 10 10 0 0 BKV 58 83 57 84 / 0 0 0 0 SPG 67 81 66 83 / 10 0 0 0 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...None. Gulf waters...None. && $$ UPDATE/AVIATION...Mroczka PREVIOUS DISCUSSION...MCMICHAEL/HUBBARD