Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 05/08/18

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
820 PM CDT Mon May 7 2018 .UPDATE... Issued at 818 PM CDT Mon May 7 2018 No major changes anticipated. LLJ will probably serve to keep at least some of the convection organized overnight into eastern South Dakota. Once storms get east of the Missouri valley, they`ll likely become elevated with a lesser chance of hail/gusty winds. Latest HRRR keeps a broken line of storms moving across overnight. && .SHORT TERM...(This Evening through Tuesday Afternoon) Issued at 344 PM CDT Mon May 7 2018 Two main rounds of thunderstorms will be possible through Tuesday afternoon, both in response to an incoming shortwave which is currently positioned across southern Montana. The first round may develop this evening across western South Dakota by 23z and head east through the overnight. Several CAMs are picking up on this idea, as a combination of 1000+ J/kg of CAPE, steep low level lapse rates and around 20 knots of deep layer shear provide a favorable environment. By sunset, a multicell cluster of storms may be underway across central SD. MLCAPE will have taken a nosedive, but this cluster may be sustained due to a strengthening LLJ of 45+ knots across central/northeastern SD. A few storms may reach severe limits at times across portions of western and even central South Dakota, but generic to strong thunderstorms will be most likely across the majority of the CWA with gusty winds and some small hail being the main threats. The second main round of thunderstorms are expected to develop near and southeast of the surface low Tuesday afternoon/evening once the atmosphere has a chance to destabilize. Dewpoints into the 50s, CAPE in the 1000-2000 J/kg range, and low- level shear may once again provide a marginal environment for a few strong to severe thunderstorms. The area of greatest concern will be focused along a surface trough extending from the low, in central South Dakota, southeastward into southeastern South Dakota. .LONG TERM...(Tuesday Evening through Monday) Issued at 344 PM CDT Mon May 7 2018 When the period opens, a low pressure system is departing the region, resulting in decreasing precipitation chances Tuesday night into Wednesday. Dry conditions should be in place for most of Wednesday through Thursday before the next low pressure system moves in, bringing more precipitation chances mainly anchored on Thursday night into Friday. Beyond that, forecast confidence really dwindles with an upper level rex-block pattern of sorts developing. Models tend to mishandle system track/timing in blocky patterns. At the moment, not all that confident that this forecast areas sees much in the way of precipitation chances beyond Friday. The 12Z deterministic GSM models continue to trend cooler with low level thermal advection progs beyond Wednesday. Temperatures could be running near to a few degrees below climo normal during the second half of the week into the weekend. Still not seeing a lot of support for that scenario in the NAEFS Ensemble S.A. table. 850hpa standardized anomaly output suggests temperatures could still be one or more standard deviations above normal beyond Wednesday. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday Evening) Issued at 659 PM CDT Mon May 7 2018 Outside any thunderstorms, conditions will be mostly VFR through the night. Lower visibility and cigs can be expected with thunderstorms. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. && $$ UPDATE...TDK SHORT TERM...Lueck LONG TERM...Dorn AVIATION...TDK
Area Forecast Discussion
National Weather Service Glasgow MT
925 PM MDT Mon May 7 2018 .DISCUSSION... 930PM UPDATE: Changes to the near-term forecast was to adapt PoPs for the next couple hours to current radar trends and blend that into newer model data going forward. RAP and SREF appeared to have the best representation of the current observations and radar spatial coverage. Most other things in the forecast look to be on track. GAH AFTERNOON DISCUSSION: Generally updated the precipitation forecast for the forecast period. With ongoing stronger thunderstorms to the south, small hail and gusty winds were included in the forecast through midnight for areas along and south of Hwy 200. These storms seem to be driven mainly by diurnal heating. With no shear support present, the storms seem fairly vertically stacked, and therefore generally are lasting approximately an hour or so. Otherwise, the forecast was relatively unchanged from this morning. Bigelbach MORNING DISCUSSION: Upper ridging over the area will move off to the east today, closely followed by a shortwave trough moving in from the west. The ridge is expected to move out slowly enough that high temperatures across areas from Valley and Garfield counties and east are anticipated to once again make it to the low to mid 80s. Phillips and Petroleum counties may not get quite as warm as the influence of the shortwave should limit the amount of solar insolation across those areas today. The shortwave will bring with it a chance of showers and thunderstorms. Thunderstorm chances will be greater over areas that receive the most surface heating during the day. Northwest flow aloft returns to the area Tuesday, and another shortwave trough will move across the region, bringing another chance of showers and thunderstorms to northeast Montana. Another ridge will briefly set up over the area Wednesday, leading to dry weather for most of the day. This will quickly flatten out as yet another shortwave approaches, so temperatures will not get much warmer than they were on the previous day. Showers return Wednesday evening into Thursday morning yet again with this disturbance. Beyond this, model consensus shows a pretty strong area of low pressure diving from the Pacific Northwest into the Great Basin region Friday and then potentially across the Rockies on Saturday, but guidance diverges regarding how far northward the moisture makes it. The ECMWF and Canadian models have at least our southern zones receiving more rain, while the GFS misses northeast Montana almost entirely. Assuming the latest forecast pattern pans out, would not be surprised if the wetter pattern is closer to what eventually occurs. For now, went with the latest model blends. Hickford && .AVIATION... FLIGHT CAT: VFR-MVFR SYNOPSIS: Low pressure system across the areas may continue to bring a few scattered showers, but these should diminish in coverage overnight. Ceilings will generally remain at VFR. However some MVFR ceilings could sneak into KGDV mid morning. WIND: north to northeast at 5 to 10 kts overnight... becoming light and variable Tuesday afternoon... then gaining a western component Tuesday night. Bigelbach/GAH && .GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE. && $$
Area Forecast Discussion
National Weather Service Green Bay WI
618 PM CDT Mon May 7 2018 Updated aviation portion for 00Z TAF issuance .SHORT TERM...Tonight and Tuesday Issued at 231 PM CDT Mon May 7 2018 The latest RAP analysis and satellite/radar imagery show high pressure centered from the mid-Mississippi Valley to the central Great Lakes early this afternoon. Mostly sunny skies are prevailing across the region, with only a little cu popping over western WI and the Upper Peninsula. Meanwhile, humidities are falling into the low to mid 20s over parts of the northwoods, where temps are in the mid to upper 70s and winds are gusting up to 20 kts. Looking upstream, mid clouds are on the increase across the Dakotas ahead of the next low pressure system. Forecast concerns revolve around lingering low humidities into Tuesday and precip chances on Tuesday afternoon. Tonight...High pressure will continue to shift to the east into New England and the Ohio Valley. Increasing mid-level moisture will lead to 10 kft clouds pushing across northwest and north- central WI late in the night. Until then, should see mostly clear skies with a light southwest wind. Warmer lows ranging from the mid 40s near the U.P. border to the mid 50s over the southern Fox Valley. Tuesday...Low pressure will continue to move east across the eastern Dakotas and into the northern Mississippi Valley. As the low draws closer to the state, clouds will be on the increase from west to east through the day. The clouds will be running into a very dry airmass, which should keep the morning dry. However, as pwats climb above 1.00 inches, will see a chance of showers climb in the afternoon, particularly over far northern WI where a weak front will drop south over the Upper Peninsula. Perhaps could see up to 200 j/kg of cape around Iron Mountain, though with the dry air, will keep chances of showers low, and thunder out of the forecast. Perhaps a few other showers could drift into north- central WI late in the day within the mid-level theta-e advection zone. With the clouds arriving from the west, north-central WI should see slightly cooler temps, while eastern WI will likely reach the upper 70s. .LONG TERM...Tuesday Night Through Monday Issued at 231 PM CDT Mon May 7 2018 Precipitation trends for Wednesday/Wednesday night, and Thursday night through Saturday night periods, are the main forecast concerns. A lingering frontal boundary and increasing low-level jet should generate scattered showers over our western and northern counties Tuesday night. Rain chances will increase Wednesday into Wednesday night as a low pressure system and associated upper level trough move through. Given precipitable water values increasing to 1.0 to 1.4 inches and the amplitude of the upper trough, we should see a quarter to a half inch of rain with this system. Some elevated instability will support a small chance of thunderstorms, especially over central and east central WI. Generally dry conditions are anticipated on Thursday into Thursday evening as Canadian high pressure passes through. Forecast confidence remains low for the rest of the forecast period due to differences among the medium-range models. A strong frontal boundary will set up just south of the region, with periods of moderate to strong overunning occurring at times due to a 30 to 40 knot low-level jet. Though there is no true concensus, the blended model data supports the highest precipitation chances late Thursday night into Friday, and again on Saturday, mainly across central and east central WI. Thunder will also be possible over our southern counties during this period. The bottom line is that a round or two of significant rainfall is possible later in the week, which could cause flooding concerns to flare up again. Temperatures will start off near normal, then drop to much below normal by Friday and Saturday. Cannot rule out a rain/snow mix over far northern WI late Thursday night, though confidence is low. && .AVIATION...for 00Z TAF Issuance Issued at 618 PM CDT Mon May 7 2018 A stable layer of air coming off of Lake Michigan on south- southeast winds have kept any mid-clouds away from eastern Wisconsin early this evening. Upon sunset, most of these initial clouds should dissipate before more mid/high clouds arrive late tonight into Tuesday morning. VFR conditions to prevail tonight and Tuesday before cigs/vsbys drop Tuesday night as our next weather system moves into the region. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....MPC LONG TERM......Kieckbusch AVIATION.......AK
Area Forecast Discussion
National Weather Service Huntsville AL
831 PM CDT Mon May 7 2018 .NEAR TERM...(Tonight) Issued at 830 PM CDT Mon May 7 2018 The storms earlier this afternoon developed as a result of a weak frontal boundary and weak upper shortwave dropping south across the area. Much of the stronger activity is now out of the area. However, a few lingering showers continue to form off of remnant outflow boundary interactions. A rumble or two is possible as latest RAP analysis puts about 500 J/kg of MUCAPE over the area but this activity will be very isolated. Expecting all precip to end with in the next hour or two and have don`t have any PoPs in past 10 pm. Debris cloudiness from these showers/storms remains over the area and has help temps up by a few degrees compared to sites to our N/NW. But as a surface high continues to build into the OH Valley and the upper level wave shifts south expect clouds to dissipate. Drier air over KY/N TN begins to move south overnight lowering dewpoints into the lower 50s (if not there already). Temps tonight should bottom out in the low to mid 50s, which is slightly below normal for this time of year. .SHORT TERM...(Tuesday through Wednesday night) Issued at 230 PM CDT Mon May 7 2018 The sfc high looks to become better established across the region starting Tue, as additional weak sfc ridging moves into the Gulf Coastal areas out of the srn Plains. This should translate into quiet and warm conditions for the mid TN Valley, as drier mid level air above H85 filters into the region from the N/NW. Weak upper ridging out of the srn/mid Plains also looks to briefly move into the region in the Tue/early Wed time frame, aiding with the dry/warm pattern. Afternoon temps both days look to climb again into the near 80F/lower 80s range, which is perhaps near/just above normal values for this time of the yr. Lows Tue night look to again trend predom in the mid/upper 50s. The overall wx pattern may then begin to change heading into late Wed afternoon/Wed night, as both the sfc/upper ridge over the region weaken in response to an upper trough pattern digging ewd across the nrn/mid Plains states. Another frontal system is also expected to lift newd out of the mid Plains on Wed, with the trailing cold front perhaps stretching into the Lower MS Valley. Some discrepancies exist between the 12Z GFS and ECMWF/NAM whether the front will move ewd into the area by Wed night, with the GFS the more aggressive and showing some convective activity developing along/ahead of this next front. Given the inconsistencies between the latest model runs, will maintain low chances of showers/tstms developing Wed afternoon into Wed night, if some semblance of the boundary can move into the area. .LONG TERM...(Thursday through Sunday) Issued at 230 PM CDT Mon May 7 2018 An upper-trough over the Northern Plains will shift into the Great Lakes and upper-Ohio Valley late Wednesday night into Thursday, dragging a cold front south into the Tennessee Valley. Based on the latest model guidance, the remnants of a MCS will move south into Tennessee during the early morning hours on Thursday. This activity will continue to weaken as it moves into a more unstable air mass across the Tennessee Valley. However, additional redevelopment of showers and storms is expected along/near this boundary again Thursday afternoon and evening -- especially if some destabilization occurs during the day. Given the weak shear, most of this activity will be fairly disorganized and outflow driven. However, a strong storm or two may be possible before sunset. Models disagree with coverage somewhat, with the GFS being more aggressive with redevelopment than the NAM/ECMWF (which keeps the best coverage over NE AL and E. TN -- closer to the better frontal forcing). Still, think that scattered convection is plausible both Thursday afternoon and evening, and have stuck close to SuperBlend for these periods. Convection should wane quickly with the loss of heating by late Thursday evening, though a rogue storm or two could linger overnight. Another weak disturbance will shift from the Mid South into the Southern Appalachians on Friday, resulting in another shot for isolated to widely scattered showers and storms on Friday. However, most areas on Friday should remain dry and pronounced warming trend will begin thanks to a building subtropical ridge to the southwest. Highs on Friday are progged to climb into the mid to upper 80s. As mentioned, this ridge will continue to build into the region this weekend, promoting mostly sunny and dry conditions. A noted increase in thickness values and temperatures aloft will help highs reach the upper 80s to perhaps the lower 90s both days. Have forecasted 90 degrees at KHSV and KMSL on Saturday, the first of the year so far at each site. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 620 PM CDT Mon May 7 2018 Weak frontal boundary that generated isolated shra/tsra is moving south of the terminals and any lingering activity should stay away from TAF sites. SCT/BKN cigs around 7,000 feet may continue for a few hours but then clear skies expected overnight. Drier air should prevent any storms from developing Tuesday afternoon. Winds remain light and variable through the period but tend to favor a N/NW direction. && .HUN WATCHES/WARNINGS/ADVISORIES... AL...NONE. TN...NONE. && $$ NEAR TERM...Stumpf SHORT TERM...09 LONG TERM...AMP.24 AVIATION...Stumpf For more information please visit our website at
Area Forecast Discussion
National Weather Service Wilmington NC
943 PM EDT Mon May 7 2018 .SYNOPSIS... Considerable clouds and an isolated shower will linger into Tuesday as a weak upper level disturbance moves slowly across the eastern Carolinas. Dry high pressure will dominate midweek. Deeper moisture will begin to flow northward late week and during the weekend with isolated showers and thunderstorms popping up in the summerlike heat and humidity. Showers and thunderstorms should increase ahead of a cold front early next week. && .NEAR TERM /THROUGH TUESDAY/... As of 930 PM Monday...The leading edge of the low clouds has slid across the state line and is now approaching North Myrtle Beach. Interestingly, farther north and "deeper" into what should be the heart of the area of low-level moisture, clouds appear to be fragmenting according to airport observations and GOES-16 10.3-3.9 micron difference imagery. The latest HRRR has a decent initialization and shows the low clouds sliding through all of Horry County in the next 2 hours, but also shows a continued erosion of clouds across the Cape Fear region and farther north into eastern North Carolina. Based on the rich moisture observed in the 950-900 mb layer (roughly 1500-3000 ft AGL) on the 00Z MHX sounding I am not convinced I need to reduce overnight sky cover forecasts too much. Changes near the coast include adjustments to sky cover based on current observations and the 18Z GFS and latest HRRR, and an small upward adjustment to wind speeds. Very few changes are needed back across the Pee Dee region where it appears the moisture will have trouble reaching due to 950-850 mb winds veered with just enough westerly component of motion to keep dry air in place. The western edge of the low clouds will probably end up reaching a line from Lumberton to Dillon to just west of Georgetown around midnight. Low temperatures should generally reach the upper 50s, perhaps a little warmer along the beaches and a little cooler from Lumberton to Bennettsville. Discussion from 300 PM follows... Much of the stratus has broken up into an extensive stratocu field leaving partly to mostly cloudy skies, except from eastern half of Brunswick, Columbus and Pender counties eastward to the coast. This is where a blanket of stratus continued to cutoff most of the sunshine. Expect to see some brightening in this northeast corner of the forecast area, but overall, this low level moisture will persist through tonight along the coast, where elsewhere will see a mix of sun and clouds. Temps were into the mid 70s over the eastern half of the forecast area with readings up near 80 degrees west of I-95. A weak sfc trough will remain off shore, extending north toward Hatteras while a mid to upper low will swing slowly east through the Carolinas through Tues, pushing a boundary slowly east. There were some showers associated with this boundary out west toward the mountains where better lift was located. Still expect some isolated showers later today as some afternoon heating combines with modest height falls associated with mid to upper level trough moving in from the west. Expect a similar scenario Tues aftn with stratus lifting and stratocu through the aftn with max heating and cool air aloft to produce isolated shwrs although the mid to upper levels will remain quite dry. A cooler northerly flow will continue through the period with some higher gusts. Lows tonight will drop into the mid 50s to around 60, and will rebound back into the mid 70s to the northeast portion of forecast area and up closer to 80 over Florence and southwest portion of forecast area. && .SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/... As of 300 PM Monday...Surface ridge axis extends south into the Carolinas Tuesday night from a center all the way up on Ontario, Canada. In the upper levels a trough will be moving off the coast. Most of the column will be quite dry according to forecast soundings, but a very shallow surface-based layer of saturation below the subsidence inversion. This moisture is more prevalent at the coast compared to inland. On Wednesday the ridge axis gets pinched off from its parent high and a weak high pressure center becomes established across the Carolinas. Expect mostly sunny sky (some cu should develop) and seasonable to slightly mild temperatures. Wednesday night again finds some low level moisture trapped beneath inversion and some fog may develop with the high overhead bringing such light winds. && .LONG TERM /THURSDAY THROUGH MONDAY/... As of 300 PM Monday...A ridge of high pressure will be situated offshore. Mainly weak mid level shortwaves, residing in the stronger flow, will pass by to our N late in the week. Weak low pressure in the Gulf of Mexico coupled with high pressure further east will help steer increasing moisture N during the weekend and early next week. This area of low pressure may drift N across portions of the Southeast states early next week ahead of a trough and surface cold front approaching from the W. Will therefore show POPs increasing, especially early next week. Will keep it dry Thu, but expect as precipitable water values begin increasing, mainly isolated diurnal showers/thunderstorms will develop Fri through Sun with the seabreeze and Piedmont trough aiding in focusing this better supply of moisture. Precipitable water values will peak between 1.75 and 2 inches Mon as the depth of moisture increases significantly, signaling the potential for a greater coverage of convection by then. Warm temperatures are expected this period with highs well up in the 80s Thu and lower 90s inland Fri and Sat. As you near the coast, temps will not be quite as warm due to seabreeze influences, but still above seasonable normals. As the atmosphere moistens, more in the way of building diurnal clouds and showers and thunderstorms should keep temps from getting quite as warm Sun and Mon. What will be quite evident during this stretch is the influx of higher dewpoints and thus higher relative humidity and many will likely begin noticing the higher levels of humidity this weekend and Mon. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... As of 00Z...Surface low pressure centered off Cape Fear this evening, coupled with a surface ridge nosing down across the interior Carolinas will result in a northeast surge overnight. Low- level moisture across eastern NC will push southward overnight and expect IFR ceilings to impact KILM at times. IFR ceilings may also develop along the SC coast after midnight, but moisture decreases further inland. Skies should scatter out by Tuesday afternoon, although MVFR ceilings may persist longer at KILM, as it will be impacted longer by wraparound moisture. Extended Outlook...VFR. && .MARINE... NEAR TERM /THROUGH TUESDAY/... As of 930 PM Monday...The north-northeasterly wind surge is here. Gusts as high as 20-22 knots inside the coastal waters near Cape Fear are spreading southward down the coast. Areas of drizzle are possible near the thicker low clouds near the leading edge of this wind surge, and visibility could be lowered to 4-5 miles at times. Sea heights currently only 3-4 feet should build due to increasing wind speeds overnight, and the `exercise caution` headline will remain posted for the NC coastal waters. -TRA Discussion from 300 PM follows... A trough will linger and run up from weak low pressure well off the SC coast up toward Hatteras tonight into Tuesday. As this trough becomes better defined through tonight and as a weak upper level disturbance swings closer toward the coast, expect a northerly surge in winds. Overall, expect northerly winds becoming slightly more NE through tonight into Tues, reaching up to 15 to 20 kts overnight, mainly in the outer waters. Issued a precautionary statement for mainly outer waters from Cape Fear northward as seas reach up to 5 ft and winds up near 20 kts. A SE swell will combine with wind wave to produce seas up to 3 to 5 ft overnight, with peak right around daybreak on Tues. Northerly winds and seas will subside slowly heading through late Tues into Tues night. SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/... As of 300 PM Monday...North to northeast winds Tuesday night will be the product of high pressure extending into the Carolinas from Ontario, Canada as well as weak low pressure well offshore. Lingering swell energy paired with the relatively small wind waves will still yield 3 to 4 or even a few 5 ft seas, the latter towards the outer reaches of the 20nm zones. On Wednesday the low moves off to the NE and the high settles into the Carolinas. This lightens the gradient allowing for a decrease in wind wave energy. Swell energy will also be on the wane. Winds become light and variable by Wednesday night but there will still be enough of a lingering swell to prevent seas going minimal as they do with such light winds. LONG TERM /THURSDAY THROUGH SATURDAY/... As of 300 PM Monday...The last of the NE flow Thu morning will shift to the S Thu afternoon and eve as a robust seabreeze circulation develops. S winds will veer to SW Thu night and Fri with another robust seabreeze expected to develop Fri afternoon and eve. The wind direction will back slightly due to seabreeze influences both days. On Sat, as the area of high pressure offshore loses some influence and low pressure in the Gulf of Mexico drifts a little closer, the prevailing surface winds will back to S across the Carolina waters. The highest winds this period will be sustained at 10 to 15 kt with gusts near or above 20 kt during the peak of the seabreeze circulation. Seas will be 2 to 3 ft Thu and mainly 3 ft Fri and Sat. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...None. NC...None. MARINE...None. && $$ SYNOPSIS... NEAR TERM...TRA SHORT TERM...MBB LONG TERM...RJD AVIATION...CRM
National Weather Service Jackson KY
1125 PM EDT Mon May 7 2018 .UPDATE... Issued at 1120 PM EDT MON MAY 7 2018 A few showers still linger across the Big Sandy region, but this should continue to diminish overnight. Grids were refreshed accordingly with temperatures also freshened up. UPDATE Issued at 925 PM EDT MON MAY 7 2018 With the loss of daytime heating, convection has been weakening in intensity. However, convection still lingers across parts of the Big Sandy region and pops have been included there over the next hour or two to account for this. Otherwise, hourly grids have been adjusted based on recent observation and radar trends. With clearing or breaks in the clouds in locations outside of convection already in place along with winds becoming light, fog is expected to develop generally around or after 2 AM. && .SHORT TERM...(This evening through Tuesday night) Issued at 440 PM EDT MON MAY 7 2018 19z sfc analysis shows low pressure lingering over the Southern Appalachians helping to generate scattered showers and thunderstorms for the eastern 2/3rds of the CWA. The convection is a bit more robust and further northwest than initially forecast with the HRRR doing a better job at capturing it than the NAM12. This has also created a decent cu field, but the clouds did little to hold back temperatures so that readings reached the low and mid 70s most places. Meanwhile, dewpoints are mainly in the low to mid 50s while winds away from any storms are light blowing from the north to northwest. The models are in good agreement aloft through the short term portion of the forecast. They all have the trough over the Ohio Valley sinking into the Southern Appalachians and closing off tonight along with a swirl of mid level energy. This low moves slowly east through Wednesday morning taking the core of its energy along with it and allowing heights to rise in its wake for a time through 12z Wednesday. Given the agreement among the models aloft will favor a general blend, though with a lean toward the higher resolution HRRR and NAM12 for details. Sensible weather will feature scattered diurnally driven convection taking advantage of fairly decent sfc moisture in place and a cold pool aloft. Look for these to fade out toward sunset leaving mostly clear skies behind. Similar to last night, radiational cooling will likely encourage fog to form in the river valleys - becoming dense toward dawn. The inversion and radiational cooling will also set up a decent ridge to valley temperature split tonight. Similar weather conditions follow for Tuesday with still a chance for isolated to scattered showers and storms developing in the afternoon - though they should be more easterly than today`s batch. Another ridge to valley temp split is anticipated Tuesday night along with some patchy valley fog toward dawn. Again used the CONSShort and ShortBlend for all the grids through the short term portion of the forecast. Did make the most significant adjustments to the temperatures each night for terrain effects. As for PoPs, went higher than guidance this afternoon and again on Tuesday afternoon. .LONG TERM...(Wednesday through Monday) Issued at 340 PM EDT MON MAY 7 2018 As a surface low pressure system makes its way across the Plains, upper level ridging will be in place over the OH Valley for Wednesday. This will lead to a brief period of generally dry weather before a cold front progresses over the Commonwealth Thursday. The front will stall over the region on Friday as a stationary front before lifting to the north over the weekend. This pattern will incite southerly flow, bringing warm and moist air up from the Gulf. The GFS shows the best instability later on Thursday, with about 1500 J/kg of MUCAPE. Therefore, the best chance at precipitation and storms will be on Thursday. However, rain/storms will be possible at times through the weekend, diminishing Sunday afternoon. Another system is possible for Monday, but will continue to monitor future model runs to assess development and trends. High temperatures will be in the low 80s Wednesday through Thursday. With the southerly flow, temperatures will be on the increase for Friday and into the weekend where temps will reach the mid to upper 80s. Low temps for the extended will generally remain in the 60s. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) ISSUED AT 840 PM EDT MON MAY 7 2018 Generally VFR conditions will prevail over the next few hours outside of isolated to scattered convection in the far southeast part of the area. Most of the convection should diminish by 3Z or 4Z. Opted to include VCTS at KSJS for the first few hours of the period for this. Lingering cumulus outside of the remaining convection should diminish by 2Z with some mid level ac lingering in some locations. With winds slackening and skies clearing following precipitation that has fallen over the past couple of days, fog likely will form again after 06Z. Vis in this should fall to at least the MVFR range in several locations with some valley locations experiencing some dense fog and VLIFR vis. The fog should lift and dissipate between 12Z and 14z. Outside of initial convection, winds should remain light and variable tonight, before averaging out of the northeast to east at 5 to 10 KT from 16Z on. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JP SHORT TERM...GREIF LONG TERM...CGAL AVIATION...JP
Area Forecast Discussion
National Weather Service Miami FL
744 PM EDT Mon May 7 2018 .AVIATION...Seabreeze collision ongoing over interior with most convection away from TAF sites, but isold SHRA can`t be ruled out vcnty KFLL-KTMB through 02Z. Winds become light/vrb overnight with front passage, picking up out of the NE after 13Z. East coast sites expected to see gusty ENE winds 12-15kts through afternoon hours with WNW Gulf breeze at KAPF after 18Z. Rain chances lower tomorrow with drier air, with main threat once again over interior with seabreeze collision. && .UPDATE... Late seabreeze-initiated showers and isolated thunderstorms over the Everglades and inland SW Florida this evening will drift east and gradually wind down over the next 2-3 hours. The HRRR model continues to insist on further development to the east over at least the western suburbs of Miami/Fort Lauderdale, and while that model has been somewhat overdone with the precipitation so far today, it`s certainly not out of the question that at least a few of these cells could affect the populated areas of the east coast metro area. Therefore have left in 30% POPs for the general Miami/Fort Lauderdale through the late evening hours, with 10-20% elsewhere. Diffuse front moves through area later tonight, causing winds to become more NE-N with lingering isolated showers over far SE Florida and the Atlantic waters. && .PREV DISCUSSION... /issued 339 PM EDT Mon May 7 2018/ DISCUSSION... REST OF TODAY AND TONIGHT: Latest WPC surface analysis shows the cold front currently oriented NE to SW from Palm Beach to Collier County and the pre-frontal trough has moved offshore over the Atlantic waters and the Bahamas. The front will continue to slowly move south this afternoon and passing through later tonight. Scattered showers and a few storms are expected to develop with the daily heating and along the sea breeze. Development should initialize over the interior and then work its way towards the east coast later this evening. Most of the showers and storms will be concentrated in Broward and Miami-Dade counties. As the front moves through most of the convection should begin to diminish. The front will reach the Florida Straits stall and wash out across the area. Low temperatures tonight will range from the lower 60s across the interior and Lake Okeechobee region to near 70 along the Gulf coast and the mid 70s along the east coast. SHORT TERM: After the frontal passage a much drier and stable airmass will slowly filter into South Florida. Rain chances on Tuesday will decrease with some lingering moisture a few showers are possible but POPs will remain below 30 and continue to decrease as the drier air continues to filter in Tuesday night and Wednesday. Low to no rain chances Wednesday and during the day on Thursday. Wind flow will be northeasterly becoming more easterly through the middle of the week. High temperatures will be in the mid to upper 80s with temperatures around 90 in the interior and Gulf coast regions. Morning lows will be in the mid 60s near Lake Okeechobee region to mid 70s along the east coast. LONG TERM (Thursday through the Weekend): Models continue to show a moisture surge back into South Florida from the Caribbean towards the end of the week and into the weekend. Model soundings show precipitable water values rising to above 2 inches Friday through Sunday well above the average of 1.3 for this time of year. Models are beginning to hint at a mid-level low pressure system possibly developing off the west coast of Central Florida which would continue to pump moisture over the Florida Peninsula. Rain chances will begin to increase Thursday night continuing through the weekend. Confidence continues to increase that a wet weekend is in store across South Florida. In the long term high and low temps will be around normal for this time of year. MARINE...A weak front is currently moving through South Florida this afternoon and this evening. Scattered showers and a slight chance of thunderstorms will be possible over the Atlantic waters through tonight. Light to moderate northerly winds are expected the rest of today and tonight, before winds turn more to the east for the middle of the week. Seas will be generally 3 feet or less. Rain chances increase for the end of the week through the weekend. && .PRELIMINARY POINT TEMPS/POPS... West Palm Beach 71 86 72 86 / 20 10 0 10 Fort Lauderdale 74 87 73 86 / 30 20 10 10 Miami 73 87 73 87 / 30 20 10 10 Naples 70 90 69 91 / 10 10 10 0 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...None. AM...None. GM...None. && UPDATE...59/Molleda AVIATION...88/ALM
Area Forecast Discussion
National Weather Service Marquette MI
658 PM EDT Mon May 7 2018 .SHORT TERM...(This evening through Tuesday) Issued at 352 PM EDT MON MAY 7 2018 WV imagery and RAP analysis indicated wnw mid/upper level flow between through the nrn Great Lakes between a trough from Hudson Bay into far nrn Ontario and a ridge from the cntrl plains into the southern Great Lakes. An upstream shortwave trough was located over central Montana. At the surface, sw to s winds have increased across Upper Michigan as a ridge builds southward into the srn Great Lakes. Tonight, winds will diminish, but will remain strong enough to maintain mixing and keep temps in the 40s central and the lower 50s west. Tuesday, warm and relatively dry conditions will persist as 850 mb temps remain in the 10C-12C range with sunshinse/mixing dropping RH values into the 20-30 percent range inland. However, winds will be lighter at 5-10 mph with gusts only to 10-15 mph. Otherwise, a weak cold front will drop through nrn Upper Michigan which will result in falling temps during the afternoon and keep readings in the 40s along Lake Superior. WAA/isentropic lift could be enough to support some sct light rain showers into the west by late afternoon. The forecast leans more toward a gradual movement of pcpn into the area, given the dry antecedent airmass. .LONG TERM...(Tuesday night through Monday) Issued at 313 PM EDT MON MAY 7 2018 After heightened fire weather concerns much of the last couple weeks, expected pattern will become cooler and more moist so may see the fire concerns begin to lessen somewhat as spring green up gets more underway. Temperatures will be on a bit of a roller coaster the next week. Temps will start this week well above normal but will trend toward normal by Wed and then well below normal for Thu-Sat before bouncing back toward normal by next Mon. A chilly night Thu night with readings in the 20s likely inland. A bit early for specifics, but there are indications that some areas of Upper Michigan could see total precipitation amounts over 1 inch through next weekend. If this works out that would definitely help alleviate the fire weather concerns at least in those areas, but there is still uncertainty in whether all areas will see appreciable rainfall. Appears the rain would come in two main waves, first with the passage of a cold front/low pressure system late Tue night through Wed. Main low is expected to track from the northern Plains across WI and lower MI on Wed. Strongest moisture advection and elevated instability should remain south of Upper Michigan but since the low is tracking along to the south, parts of especially western Upper Michigan could see heaviest rain due to fgen and upper divergence. Heaviest rain, 0.5 to 1.00 inch, would occur late Tue night through midday Wed. After this low exits to east of Lk Superior and Upper Michigan late Wed night, high pressure building southeast out of Manitoba will bring dry weather for Thu. Winds will be from the northwest on Thu and could see gusts over 30 mph on Thu morning, especially east half of Upper Michigan. Late this week with quick west flow aloft and main sfc low well to southwest over southern Plains and a warm front extending toward WI and lower MI, think batch of moderate to heavy rain to stay south of Upper Michigan late Thu night through Fri. Should see cool conditions along with a lot of clouds and maybe some fog as well due to east to northwest winds persisting north of the front over WI and Lower MI. Next chance of rain moves back in later Fri into next weekend. Main question is how far north will wave of rain slide into Upper Michigan. Latest ECMWF trended farther south so a bit drier especially over the far north and northeast forecast area. Southern U.P. will be most favored to see the rain with potentially rest of our forecast area missing out as west to east frontal boundary and right entrance region of upper jet stay just south of Upper Michigan as upper level flow remains zonal/parallel with the front. Another trough moving through in what looks like more of a northwest flow aloft could bring smaller chance of rain by end of the long term. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 658 PM EDT MON MAY 7 2018 VFR conditions are expected at all sites through the TAF period. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 313 PM EDT MON MAY 7 2018 Mainly light winds of 20 kts or less can be expected through Wed as the pressure gradient remains weak. Next chance of stronger winds of 25 to 30 kts develops late Wed night through Thu morning, especially over the east half of Lk Superior, as winds shift to the northwest behind a low pressure system/cold front. Winds diminish to 20 kts or less late Thu into next weekend. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...JLB LONG TERM...JLA AVIATION...07 MARINE...JLA