Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 05/02/17

Area Forecast Discussion
National Weather Service Gaylord MI
1040 PM EDT Mon May 1 2017 .UPDATE... Issued at 930 PM EDT Mon May 1 2017 Pronounced stacked low pressure system now over NE Wisconsin this evening with a surface trough axis stretching eastward through the tip of the mitt/straits secondary surface low over SE Ontario. North of the trough...still rather soupy with low stratus and areas of dense fog...particularly in the tip of the mitt where surface winds remain easterly off Lake Huron. Meanwhile...a few pockets of showers continue to pinwheel around the upper lifting up through eastern upper Michigan followed closely by another lifting through northern lower Michigan. Another lull in the precip behind that...but with yet another batch rotating out of SE Wisconsin that will be swinging up through the region overnight. So...periodic showers with likely-categorical POPS is the overall forecast idea for the rest of tonight. Have attempted to add some hourly timing detail to shower chances through tonight into Monday morning (with the help of HRRR hourly guidance). Otherwise, no big changes to the ongoing forecast. && .NEAR TERM...(Tonight through Tuesday) Issued at 227 PM EDT Mon May 1 2017 ...Scattered to numerous showers... High Impact Weather Potential: Minimal. The center of the surface area of low pressure has progressed into central Wisconsin with an associated occluded front now into far northern lower Michigan (near the tip of the Mitt). Apx radar showed a few showers scattered around. The main near term forecast concerns revolves around pops through Tuesday. Will not get overly detailed with the forecast through Tuesday. Upper level and surface low pressure system will continue to track slowly northeast through the period (to near Sault Ste Marie at 12z Tue) while dragging a surface cold front across the region later tonight. Upper level energy will pinwheel northward into the region as well with wrap around moisture on the backside moving into northern Michigan into the day on Tuesday. Therefore...expect scattered showers to become numerous in some areas by this evening and continue into tonight. Shower activity should be more scattered on Tuesday. Additional rainfall amounts tonight into Tuesday should be a quarter of an inch or less. Temperatures will cool down once again behind the cold front. Lows tonight in the upper 30s to lower 40s. Highs Tuesday only in the middle to upper 40s which is quite chilly for early May (about 15 degrees below average for the date). Expect minor flooding to begin on the Rifle River near Sterling in Arenac County this evening and continue through midweek. This is due to the rain that fell over the last couple of days as well as any additional rainfall through Tuesday. && .SHORT TERM...(Tuesday night through Thursday) Issued at 227 PM EDT Mon May 1 2017 ...Drier and milder times ahead... High Impact Weather Potential: Minimal. Pattern Synopsis/Forecast: Current wet-weather producing system will be on its way out to start the short term portion of the forecast. While broad troughing will no doubt remain at the mid levels, entrance of surface high pressure will bring moderating temperatures and drier weather along with it. Mid range guidance progs in rather remarkable agreement of a sharping of the the mid and upper level flow regime by Thursday, with energy dropping on front side of expanding western ridge helping carve out closed mid level low pressure well to our south. While any influences of this system up this way (if any at all) look to occur further out in the extended, much weaker northern stream energy diving southeast within deepening trough axis may bring a few light showers by later Thursday to at least parts of the area. Primary forecast concerns/challenges: Cloud and temperature trends and addressing that possible late day shower potential on Thursday. Details: Any lingering showers, perhaps even mixed with a touch of snow, are expected to come to an end rather quickly Tuesday night as deep moisture departs and surface high pressure begins to make an entrance. This drying trend continues right through Wednesday, with trends supporting a mainly sunny and much milder day as highs spike well into the 50s (amazing what early May sun can do). Wednesday night shaping up to be a bit on the chilly side with excellent radiational cooling expected, especially during the first half of the night when high pressure is directly overhead. Will definitely undercut guidance numbers by several degrees in those typical interior ice box locations, and would not be surprised to see some spots make a run into the upper 20s by sunrise Thursday. Another fairly mild day on Thursday is expected, this despite slowly increasing cloud cover. As mentioned, will need to be on the lookout for some late day light showers, particularly across eastern upper Michigan. Guidance blend approach recommends keeping it dry for now, but something to monitor in the coming days. .LONG TERM...(Thursday night through Monday) Issued at 227 PM EDT Mon May 1 2017 Models are in fairly good agreement with this portion of the forecast period, with an area of low pressure developing Wednesday night over the southern Mississippi River Valley, treking just southeast of the Great Lakes region and finally moving into New England by Saturday...where then models hint at a cut-off low remaining for several days. This track could produce light precipitation over the forecast area with partly to mostly cloudy skies and high temperatures in the upper 50s to low 60s. The only other indication at this time of precipitation would be with a weak upper level wave with accompanying moisture that would move through towards the end of the work week/early next weekend, producing only some light precipitation amounts. Low temperatures will be in the low to mid 30s. && .AVIATION...(For the 06Z TAFS through 06Z Tuesday evening) Issued at 1039 PM EDT Mon May 1 2017 Deep low pressure over Wisconsin this evening will rotate up into Canada late overnight into Tuesday. Several waves of light showers will rotate through the region through Tuesday, before things dry out late Tuesday and Tuesday night. Largely VFR conditions across northern lower Michigan at the moment. But CIGS lower back to MVFR later tonight and persist through Tuesday as those showers moving through. Southwesterly winds tonight veering westerly and eventually northwesterly on Tuesday with some gustiness at times. && .MARINE... Issued at 313 AM EDT Mon May 1 2017 As low pressure moves across the area tonight and Tuesday, winds will veer sw, and then w to nw on Tuesday, and will again become rather gusty. && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LH...SMALL CRAFT ADVISORY until 11 PM EDT Tuesday for LHZ349. LM...SMALL CRAFT ADVISORY until 11 PM EDT Tuesday for LMZ345-346. LS...NONE. && $$ UPDATE...TBA NEAR TERM...AJS SHORT TERM...MSB LONG TERM...TJL AVIATION...TBA MARINE...JZ
Area Forecast Discussion
National Weather Service La Crosse WI
605 PM CDT Mon May 1 2017 .SHORT TERM...(This evening through Wednesday night) Issued at 147 PM CDT Mon May 1 2017 Early this afternoon, the surface low was located over southwest Wisconsin while move slowly to the northeast. Local and regional radars continue to show most of the precipitation was in the cyclonic flow on the back side of the system from northern Minnesota into central Illinois. In addition to the cyclonic flow, the precipitation production was being aided by some weak frontogenesis in the 1000-700 mb layer and isentropic up glide in the trowal. The 01.16Z RAP indicates the frontogenesis will move east with the area of low pressure and rapidly weaken by early evening. However, a secondary band of frontogenesis currently forms to the west of the area and then moves to the east during the evening as well. The isentropic up glide in the trowal will be weak, on the order of 1 to maybe 2 ubar/s on the 285K surface, but should remain through much of the night. Expecting to see the more widespread rains move east and primarily be east of the area by early evening. However, with the secondary band of frontogenesis, continued weak isentropic up glide and cyclonic flow, cannot rule out some on and off light rain/drizzle through the night and will carry some 20 to 40 percent chances for the entire area after midnight. These chances should then end early Tuesday morning as the forcing dissipates as the surface low moves across the Great Lakes and into Ontario. While the precipitation will end Tuesday morning, the clouds will be much slower to clear as enough moisture will be stuck in the cyclonic flow to keep these around for much of the day. Some clearing could start in the western sections during the afternoon, but not expecting widespread clearing to occur until Tuesday evening. Northwest flow aloft will be established over the Upper Midwest behind the current system. A short wave trough topping the western upper level ridge will move onto the High Plains Tuesday but the bulk of the energy from this wave will go well south of the region to help form another upper level low over the middle Mississippi River Valley Wednesday. There could be enough left over energy on the northern side of this new low to bring some weak pv advection into the region for Wednesday afternoon and evening. This could be accompanied by some occasional weak up glide on the 295K surface, but in general, the forcing looks to be pretty weak with this system and will only a some small chances for showers across the western sections Wednesday afternoon and evening. .LONG TERM...(Thursday through Monday) Issued at 147 PM CDT Mon May 1 2017 There could still be just enough remaining lift from this system for a small chance of showers across the northern sections Thursday. With this system expected to become a large cut off low over the Ohio River Valley it will slow the eastward progress of the upper level ridging. This should then allow the next short wave trough topping the ridge to slide across the western Great Lakes Saturday. As this wave slides by the area, it could produce some showers that affect the eastern portions of the forecast area late Friday night and Saturday morning. After that, the ridging will continue to move slowly east and be close enough to keep the area dry to end the period. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 605 PM CDT Mon May 1 2017 Aviation forecasts will be troubled with cyclonic flow on backside of slowly exiting closed upper low. Source region is mainly MVFR ceilings with bands of rain or rain showers, and pockets of IFR conditions. Latest few HRRR runs keep at least patchy light precipitation wrapping around exiting storm which may keep threat of IFR conditions around a bit longer than earlier predicted, although this will be intermittent it appears. In any event, trend will be for precipitation to slowly exit and ceilings to gradually improve with breezy northwest winds and well mixed atmosphere. Even so should still MVFR for the most part until late in the forecasts when drier air is progged by most 12z/18z guidance to clear skies out a bit. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None. && $$ SHORT TERM...04 LONG TERM...04 AVIATION...Shea
Area Forecast Discussion
National Weather Service Taunton MA
1020 PM EDT Mon May 1 2017 .SYNOPSIS... A warm front lingers over the region much of the night, providing a focus for scattered showers and isolated thunderstorms overnight. It will be mild across much of the area tonight except remaining cool across northeast MA and the Greater Boston area. Other than a few showers Tue morning over the Cape and Islands, a drying trend develops with partial sunshine and warm temperatures for Tue afternoon. Dry and cooler weather follows Wed and Thu. Another low pressure will push toward the region Friday, bringing periods of heavy rain and gusty winds. Showers may continue into next weekend as this low pressure lingers nearby. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... Fog... Line of showers and tstms over Eastern NY is moving northeast toward VT and NH. The southern end of the line, in eastern PA, trends northeast into the Berkshire East Slopes and parts of the CT Valley 11 PM to Midnight. Meanwhile 10 pm observations show fog across Eastern MA and parts of Rhode Island. Vsbys on Cape Cod and Nantucket are already at or near 1/4 mile while areas along the MA coast and Narragansett Bay are 1-3 miles. Expect the low clouds/fog to expand through 2 AM in RI and Eastern MA. A Dense Fog advisory remains in effect along the South Coast where higher dewpoint air moves in off the colder waters. Convection... The New York convection trends northeast. HRRR projects showers moving across Southern New England overnight with diminishing elevated CAPE. Expect the current thunderstorms to diminish as they edge east into our area, but could be an isolated storm in Western MA. This initial area of showers is favored in Western MA/Northern CT 11 PM to 4 AM, and in Eastern MA and RI 2 AM to 6 AM. The HRRR shows a second line associated with the actual cold front developing along the western edge of the CAPE over Eastern NY and PA after midnight and moving into Western MA/Northern CT 4-6 AM. Will also be watching a potential area of convection moving up the coast from Virginia and the Carolinas. This is projected to move with the low level southwest jet. This may create enough low level convergence to generate a second round of thunder, but primarily over RI and SE MA. HRRR timing would bring this in after 12z. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/... Tuesday... Clouds linger across the region in the morning along with a few leftover showers over Cape and islands but drying trend late morning sets up for a very nice afternoon with partial sunshine and warm temps as highs climb well into the 70s away from the south coast! Good blyr mixing will support SW winds gusting up to 30 to 40 mph at times. This wind direction will limit highs to the 60s along the south coast. Trailing short wave/secondary cold front may trigger a few showers late in the day across the interior. Otherwise dry weather prevails. Tuesday night... Dry weather but turning cooler behind departing short wave. Lows mainly in the 40s but that`s close to normal for early May. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... Big Picture... A high pressure to start for Wednesday and Thursday followed by a strong low pressure system that will bring heavy precipitation to the region Friday into Saturday. Rain totals may yield around 2 inches of rain in 36 hours. Details... Wednesday... With the previous frontal passage, temperatures will be much cooler and strong winds will continue as a weak high pressure builds back into the region. Westerly winds may gust up to 20 mph inland during the day, and 30 mph along the coast. Overall, Wednesday will be mostly sunny throughout the day with afternoon temperatures reaching into the 50s, with Greater Boston reaching into the 60s. Skies will be mostly clear overnight allowing temperatures to drop into the upper 30s in Northern Massachusetts. However, most of Southern New England will remain in the 40s throughout the night. Thursday... The high pressure remains for most of Thursday. With Tuesday`s cold fronts well offshore, winds continue to diminish through the day. Winds will become northwesterly early Thursday morning, as wind gusts weaken inland and along the coast. Afternoon temperatures will range from the upper 50s to low 60s across Southern New England. With a strong low pressure system approaching from the southwest, winds will become southerly in thethat afternoon and begin to strengthen along the southern coast. Overnight temperatures will range in the low 40s across Northern Massachusetts and upper 40s along the coasts. Friday... Rain showers become likely early Friday morning as widespread showers move from west to east across Southern New England. Rain will intensify Friday morning, which could reduce visibility for the morning and evening commute. Winds will quickly strengthen into the afternoon as a warm front moves north through the region. Winds could gust up to 40 mph along the coast and waters. Temperatures will be slightly below normal Friday with highs ranging in the 50s. A cold front will cross the region Friday evening, strengthening the winds even more, especially across the waters. The coast and islands may gust up to 45 mph overnight, with gusts near 30 mph inland. Overnight lows will range in the 50s across the region. Saturday... Rain will continue through Saturday morning, and taper off into the afternoon. Strong winds will continue in the east but diminish to the west. Winds Saturday afternoon will gust up to 40 mph on the Islands and 20 mph inland and along the coast. Afternoon temperatures will be in the 60s in southeastern New England, but remain in the 50s in Western Massachusetts. Saturday evening should be mostly dry as the low pressure continues northward. Overnight temperatures will range in the 40s across the region. Sunday and Monday... A cold front will cross Southern New England early Sunday morning, increasing winds behind the front. Winds will be gusting near 40 mph Sunday morning along the coast and up to 20 mph inland. Areas of light rain are possible both Sunday and Monday as a low pressure remains to the north of New England. Afternoon temperatures both days will range in the 50s with overnight lows ranging in the 40s. && .AVIATION /02Z TUESDAY THROUGH SATURDAY/... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Overnight... Scattered showers and isolated thunder likely through 06z western CT/MA and 06z-12z RI and eastern MA. Conditions lowering back to IFR in fog in Eastern MA and RI with LIFR near the coasts. Marginal LLWS from low level southwest jet. Tuesday... Mix of IFR-MVFR in the morning but trending to VFR by late morning into midday from west to east. Any lingering showers with embedded thunder early over Cape and Islands will move rapidly offshore. Remainder of the day dry with isolated or widely scattered showers late afternoon/early evening western- central CT/MA as secondary cold front moves across the area. Tue night... VFR and dry weather. KBOS TAF...high confidence on timing of showers/isolated T-storm. Low confidence on timing of cigs and vsbys lowering tonight. KBDL TAF...high confidence on timing of showers/isolated T-storm. Low confidence on timing of cigs and vsbys lowering tonight. Outlook /Wednesday through Saturday/... Wednesday...High Confidence VFR conditions as a high pressure with mostly sunny skies. Westerly winds near 20 mph inland and 30mph along the Southern Coast. Thursday...High Confidence VFR conditions prevail as high pressure remains. Winds diminish through the early morning. Northwesterly winds become southerly in the afternoon. Friday...Moderate Confidence MVFR conditions as widespread rain moves into the region. IFR conditions may become present as large areas of heavy rain move northeast through Connecticut into Central Massachusetts. Areas of IFR will be for KPVD, KORH, and KBOS between 18z and 00z Saturday. Strong wind gusts expected throughout the day as low pressure system approaches. Easterly winds gusting up to 40 mph along the coast. && .MARINE... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. 415 pm update... Overnight... Low clouds and fog will limit vsby to 1-3 miles and with areas of 1/4 mile vsbys in dense fog. Scattered showers overnight along with isolated thunder. Southwest winds increase to 20-25 kt after 11 pm - 2 am from west to east. Tuesday... Any morning showers should be confined to Cape Cod and the Islands eastward and moving offshore. Thereafter improving trend with dry weather but gusty SW winds up to 30 kt near shore. Tuesday night... SW winds begin to diminish and become westerly. Dry weather and good vsby. Outlook /Wednesday through Saturday/... Wednesday...High Confidence Wave heights up to 7 feet along the outer waters Wednesday. Westerly winds gusting up near 20 mph inland and 30 mph along the southern coast. A small craft advisory is likely needed along the Southern coast and waters. Thursday...High Confidence Wave heights lowering throughout the day, generally up to 4 feet on the outer waters. Northwest winds will be calm through most of the day, before becoming southerly. Friday...Moderate Confidence Waves up to 9 feet along the outer waters Friday evening. Winds gusting to 40 mph along the coastline, and 45 mph along the Cape and Islands. A Gale Warning may be needed along the eastern waters. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...None. MA...Dense Fog Advisory until 2 AM EDT Tuesday for MAZ020>022. Dense Fog Advisory until 5 AM EDT Tuesday for MAZ023-024. RI...Dense Fog Advisory until 2 AM EDT Tuesday for RIZ006-007. Dense Fog Advisory until 5 AM EDT Tuesday for RIZ008. MARINE...Small Craft Advisory until 8 PM EDT Tuesday for ANZ231>234-250- 251. Small Craft Advisory from 11 AM to 7 PM EDT Tuesday for ANZ230. Small Craft Advisory from 2 AM to 7 PM EDT Tuesday for ANZ236. Small Craft Advisory until 8 PM EDT Tuesday for ANZ235-237- 254>256. && $$ SYNOPSIS...KJC/Nocera/Correia NEAR TERM...WTB/KJC/Nocera SHORT TERM...Nocera LONG TERM...KJC/Correia AVIATION...KJC/Nocera/Correia MARINE...KJC/Nocera/Correia
Area Forecast Discussion
National Weather Service Burlington VT
1039 PM EDT Mon May 1 2017 .SYNOPSIS... A cold front approaching from the eastern Great Lakes will bring a brief period of moderate to heavy rainfall this evening into the overnight hours, along with isolated thunderstorms. Winds may be locally gusty with these showers and thunderstorms from the Champlain Valley westward across northern New York. Mostly cloudy skies and isolated to scattered light rain showers will occur on Tuesday and Wednesday, as a trailing upper level low moves eastward across the North Country. High pressure will bring drier and more pleasant weather conditions on Thursday. A large area of low pressure will mark a return to unsettled weather conditions on Friday and through the weekend. && .NEAR TERM /THROUGH TUESDAY NIGHT/... As of 1039 PM EDT Monday...Have gone ahead and cancelled Severe Thunderstorm Watch #187 for our area as primary convective line continues to weaken and exit into our eastern Vermont counties where a more stable airmass of maritime origin remains in place. This line produced scattered wind damage earlier this evening, most notably across southern St. Lawrence County in the Pitcairn and Fine area where a distinct microburst signature was noted on KTYX radar. Please refer to our latest storm report summary for additional info. In the meantime, a large area of post-convective moderate stratiform rainfall continues across much of northern NY. Expect this activity to gradually progress east into Vermont over the next 2-4 hours with rainfall tapering off west to east later tonight. HRRR has continued to perform admirably this evening regarding this activity and as a matter of course have leaned heavily in its direction regarding evolution of pops/wx overnight. Low temperatures a blend of available guidance, mainly upper 40s to mid 50s. && .SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/... As of 310 PM EDT Monday...Upper low pushes further into Canada on Wednesday, terrain driven showers will continue to linger into the early evening. Showers will wind down Wednesday night with surface and upper level ridging over the North Country. Temperatures will be below seasonal normals during this timeframe with cold air in place behind departing frontal system. && .LONG TERM /THURSDAY THROUGH MONDAY/... As of 315 PM EDT Monday...Really no significant changes for the long term portion of the forecast. Thursday looks to be the last dry day of the period. A large vertically stacked low pressure system will approach Thursday night and especially Friday, widespread rainfall is expected for our forecast area. This low will remain nearby and keep the weather unsettled across our area through the entire forecast period, temperatures will be cool. && .AVIATION /03Z TUESDAY THROUGH SATURDAY/... Through 18Z Tuesday...Complex forecast for this evening with convective line of strong to severe storms progressing west- east across the area, weakening into eastern VT. Main idea is a mixture of VFR/MVFR with brief heavy downpours/gusty winds, mainly from the Champlain Valley west through 02Z. Moderate to severe turbulence possible within line of storms. Behind this activity scattered rain showers taper off overnight, then re- blossom by Tuesday afternoon as upper low approaches from the Great Lakes. Again, a mixture of VFR/occnl MVFR with this activity. Winds variable this evening, trending south/southwesterly later tonight into Tuesday and becoming a tad gusty. Outlook... Tuesday Night: VFR. Breezy. Chance SHRA. Wednesday: VFR. Breezy. Chance SHRA. Wednesday Night: VFR. NO SIG WX. Thursday: VFR. Slight Chance SHRA. Thursday Night: VFR/MVFR. Likely SHRA. Friday: VFR/MVFR. Breezy. Definite SHRA. Friday Night: VFR/MVFR. Likely SHRA. Saturday: VFR/MVFR. Likely SHRA. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...None. && $$ SYNOPSIS...Banacos NEAR TERM...JMG SHORT TERM...Neiles LONG TERM...Neiles AVIATION...JMG/Banacos
Area Forecast Discussion
National Weather Service Wilmington NC
1002 PM EDT Mon May 1 2017 .SYNOPSIS... A cold front will bring a widespread showers and thunderstorms to the area tonight. High pressure will follow for the mid-week period. A Low pressure system will impact the region Thursday into Friday and may bring widespread showers and thunderstorms and heavy rain. Expect cooler weather over the weekend behind exiting low pressure system. && .NEAR TERM /THROUGH TUESDAY/... As of 1000 PM Monday...The squall line has weakened over the past couple of hours with the strongest convective elements limited to the area around Laurinburg, NC and near the Santee River in South Carolina. The environment remains supportive of convection from both an instability/skew-T viewpoint and from a synoptic view as well. A narrow but growing zone of 300 millibar divergence aloft is situated across the coastal Carolinas. Deep ascent focused beneath this divergence should help maintain steep enough lapse rates that we won`t have to worry about capping killing off the convection. The loss of daytime heating has reduced surface- based instability to around around 500 J/kg, however as the line works its way down to the coast in the next couple of hours it will encounter dewpoints several degrees higher which should increase SBCAPE to around 1000 J/kg. This should reinvigorate convective updrafts, and along with higher precipitable water values may increase rainfall rates above and beyond what most locations along the I-95 corridor are currently seeing. Helicity across the 0-1 km layer is still 250-300 m^2/s^2 with 0-6 km bulk shear around 35 knots. However 0-3 km lapse rates of 5.5C/km or less have led to slow updraft speeds and overall lack of storm organization. Severe weather potential appears low currently, however we`ll continue to closely monitor this line as it encounters better instability late this evening. The HRRR model has been very good the past few hours and its 23Z run looks almost perfect from a timing standpoint. The line should make it down to Myrtle Beach around midnight and into Wilmington around 1 AM. Our latest updated forecast features PoPs ranging from 80 percent near Georgetown to 90-100 percent farther north and across the Cape Fear region. Few changes to forecast temperatures, still anticipated to 65-67 near the coast and around 60 inland. && .SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/... As of 300 PM Monday...A zonal mid level pattern will be in place most of the period with a transition to a southwest flow late as a deep cyclone develops across the mid Mississippi Valley. At the surface weak high pressure will be in place throughout the period. There will be a very weak surface trough moving across early Wednesday but it only brings a subtle and short lived wind shift. With precipitable water values well under an inch for most of the period pops will be near zero and even clouds will be at a premium. With the somewhat deep westerly flow temperatures will remain on the warm side although overnight lows with good radiational conditions will drop to just above climatology. && .LONG TERM /THURSDAY THROUGH MONDAY/... As of 300 PM Monday...The period will begin with low pressure vertically stacked across the Mid-Mississippi Valley. Model consensus is progressive with this system early on, bringing it slowly into the Ohio valley Fri and then up into the upper Ohio Valley Fri night. Broad low pressure may then stall as strong shortwave energy continues to rotate around the system. A general eastward drift will take the vertically stacked system across eastern Canada and New England during the weekend and Mon. Widespread showers and thunderstorms are expected to develop as the warm sector envelops the area Thu and Thu night. The highest POPs this forecast cycle are for Thu night, then ending with the passage of a cold front late Thu night and the first half of Fri, from W to E, as the region gets dry slotted. Then shortwave energy rotating around the upper low and cooler temps aloft may allow for isolated showers or even a rumble of thunder Sat, mainly across the North Carolina portions of the FA, even as much drier air works into the region in the low levels. Given the slow movement of the upper low, will carry small POPs on Sun when there may be a weak surface trough moving across the area as well. Did not include POPs above threshold for Mon. The column may be sufficiently dry that day to finally forecast a dry day, However, we may still be under the influences of the upper low and cool temps aloft such that a few showers may still develop with the heating of the day. Temps will still be above normal Thu before dropping to or below normal for the remainder of the period. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... As of 00Z Tuesday...An intense squall line of thunderstorms with tops to FL450 will move steadily eastward across the eastern Carolinas tonight, bringing excursions to IFR visibility in heavy rainfall and variable convective outflow gusts to at least 25 knots, perhaps higher. The squall line should reach FLO around 0130Z, LBT around 0230Z, and the coastal airports (MYR, ILM, CRE) between 0400-0600Z. Ahead of the squall line low stratocumulus pushing onshore with bases down to 2500 feet AGL will be accompanied by surface winds as high as 20G25KT. As the squall line pushes offshore between 0600-0700Z, clearing skies are expected with VFR conditions developing across the area. Extended outlook...Periods of IFR/MVFR conditions are possible in possible widespread showers and thunderstorms and heavier rain late Thursday through Friday. && .MARINE... NEAR TERM /THROUGH TUESDAY/... As of 1000 PM Monday...The squall line of thunderstorms has weakened inland, but is expected to regain some of its strength as it moves down to the coast in the next few hours. Synoptic winds out ahead of the storm are from the south at 20-25 knots with gusts near 30 knots. Thunderstorms could add to these gusts, but behind the storms late tonight into Tuesday morning winds should veer more westerly and diminish significantly in strength. Seas have built to 7 to 7.5 feet at the buoys near Cape Fear, with 4 to 5 foot seas reported nearshore. Dominant periods are 7-8 seconds Seas could build by another foot in the next few hours before the thunderstorms arrive. SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/... As of 300 PM Monday...Weak high pressure meandering around the region will lead to weak wind fields of ten knots or less through most of the period essentially from the west. A weak surface trough briefly leads to northwest winds early Wednesday. A better defined return flow develops late from the southeast with speeds of 10-15 knots. Significant seas will be 2-4 feet early on dropping to more of a 2-3 foot range late in the period. LONG TERM /THURSDAY THROUGH SATURDAY/... As of 300 PM Monday...There is a likelihood for Small Craft Advisory conditions late Thu through Fri night and these conditions may linger into at least Sat. Elevated seas may linger into Sat. Low pressure and its associated frontal system will bring adverse winds and sea condtions for much of the period. A warm front should move through the area Thu with a cold front to follow late Thu night and Fri morning. The marine environment will remain under the influence of a vertically stacked area of strong low pressure to our N through Saturday. SE winds will veer to S Thu afternoon and to SW late Thu night. SW winds Fri will veer to westerly by late Fri and this westerly direction will persist until the end of the period. The strongest winds, 25 to 30 kt, are expected Thu night. Wind speeds will still be 20 to 25 kt Fri with winds only slowly diminishing from there Fri night and Sat. Seas will build up to 6 to 9 ft Thu night with seas remaining above the 6 ft threshold into Fri and possibly into Sat across at least the northern waters. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...None. NC...None. MARINE...Small Craft Advisory until 2 PM EDT Tuesday for AMZ250-252-254- 256. && $$ SYNOPSIS...SHK NEAR TERM...TRA SHORT TERM...SHK LONG TERM...RJD AVIATION...TRA MARINE...
National Weather Service Jackson KY
1028 PM EDT Mon May 1 2017 .UPDATE... Issued at 1028 PM EDT MON MAY 1 2017 Based on latest observation trends, winds have continued to fall well below wind advisory criteria over the last few hours. As such, after coordinating with neighboring offices, decided to go ahead and cancel the ongoing Wind Advisory for this evening. The Wind Advisory is still in effect for tomorrow afternoon as winds are expected to pick back up with afternoon heating. Other updates were fairly minor, just loading in the latest observations to make sure the near term grids were on track with the ongoing conditions. All changes have been published and sent to NDFD/web. A new forecast package (ZFP and HWO) was sent out to reflect the changes in headline. UPDATE Issued at 755 PM EDT MON MAY 1 2017 Forecast seems to be in relatively good shape. Main updates were to load in the latest observations to make sure the winds and wind gusts, in addition to the temps and dew points, are on track with current conditions. Also tweaked sky cover a bit to match up better with ongoing trends. All changes have been published and sent to NDFD/web. No updates to the forecast package are needed at this time. && .SHORT TERM...(This evening through Tuesday night) Issued at 450 PM EDT MON MAY 1 2017 20z sfc analysis shows a strong cold front now east of the state with its line of showers and embedded strong storms moving away from the area. This front has also brought in strong and gusty winds in its wake as the skies cleared. The returning sunshine limited the dropoff in temperatures post frontal with most places even rebounding back toward the low 70s. Currently readings are varying from the mid 60s in the northwest to the mid 70s in the east. Dewpoints have come down with the dry air advecting in from the west with upper 30s noted through the mid part of the CWA and upper 40s to lower 50s on the fringes. The showers and thunderstorms did bring down some higher gusts as they moved through earlier, but the bulk of the winds today have been from the gradient ahead of the front and now deep mixing behind it. Accordingly, they are now running from the southwest at 15 to 25 mph most places with gusts to 40 mph and scattered reports of power outages and trees down. The models are in good agreement aloft through the short term portion of the forecast. They all depict a deep closed low rotating northeast from the Upper Midwest across the Great Lakes and into Canada by morning. This places Kentucky in a large trough of lower heights and fast near zonal mid level flow with energy confined mainly north of the Ohio Valley. The pattern relaxes through Wednesday morning with heights lifting and flow weakening. Given the agreement will favor a consensus model solution with a lean toward the HRRR for near term details. Sensible weather will feature breezy conditions continuing into the evening before settling somewhat. Expect a mid or just lower deck of clouds to move back in later tonight with CAA making for fairly uniform temperatures. Cannot rule out a stray sprinkle or light shower from these clouds across our northern counties and the wrap around moisture of the parent system - but measurable rain is doubtful so have kept it dry overnight. The deeper moisture then retreats north on Tuesday with partly sunny conditions expected for Tuesday. The sunny patches will encourage deep mixing again on Tuesday afternoon with strong gusty winds from the southwest anticipated. For this reason, have added another day of wind advisory to the forecast for Tuesday afternoon. Tuesday night should see more of a traditional ridge to valley temperature difference set up, though tempered by the breezy winds early in the night and some clouds moving in from the west late. These clouds will mark the approach of the next weather system forecast to be another strong one as it takes shape over the Southern Plains for mid-week. Again used the CONSShort and ShortBlend as the starting point for all the grids with some adjustments for ridge to valley T distinctions Tuesday night. Also, dampened PoPs across the north with the limited wrap around moisture keeping the mention out of the zones. .LONG TERM...(Wednesday through Monday) Issued at 300 PM EDT MON MAY 1 2017 Model solutions look fairly similar with mid and upper level features through the first half of the extended, but diverge from there. A deepening trough will form a cutoff low over the Mid-South by Thursday. This low then walks its way up the Ohio Valley leaving our area in a mean northwest flow pattern. Main differences in solutions are related to subtle disturbances or lobes of energy rounding the base of the eastern CONUS trough left in the wake of the low lifting northeast into the upper Ohio Valley. At the surface, a wave of low pressure will lift northeast out of the southern plains and through the Ohio Valley. This low pressure system deepens as it passes through the Commonwealth and appears well organized. Consequently we should see another round of respectable rainfall amounts with 48 hour totals of between an inch and two inches being produced from Wednesday night through Friday night. This system will also be responsible for a decent surge of colder air with H850 temps dropping to around freezing from Friday evening through the end of the extended window...and possibly beyond. For sensible weather, models suggest an unsettle and cooler pattern for the bulk of the extended. Temperatures appear to run at least 5 to 10 degrees below normal for this time of the year. Of particular interest is Sunday morning. COOP MOS is advertising Sunday morning lows in the mid 30s. Surface high pressure will be nosing its way into the region and skies will be clearing. Concern is for the possibility of some patchy frost. Will need to keep an eye on this potential with upcoming updates. Forecast soundings do suggest the potential for some isolated thunder ahead of the approaching surface low Thursday afternoon into Thursday evening. Thus continued to carry inherited slight chance of thunderstorms for that time period, though the slight chance for thunder was extended a bit more into Thursday evening. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) ISSUED AT 802 PM EDT MON MAY 1 2017 Gusty westerly winds continue behind a cold front that pushed through earlier today. Brisk winds will continue throughout much of the evening and into the overnight, though gusts are expected to decrease with loss of daytime heating and the ability to mix down to the surface. Expect sustained winds generally around 10 knots at the TAF sites. Clouds will also move in across eastern KY, but CIGS should remain generally low end VFR throughout the night, breaking apart as we head into the day Tuesday. Wind gusts will also begin picking back up once again during the day Tuesday as temperatures begin to warm and higher winds aloft are able to transfer to the surface. Winds should remain generally westerly, sustained between 10 and 15 during the day, with gusts of 20 knots or more by 18Z at most TAF sites. && .JKL WATCHES/WARNINGS/ADVISORIES... Wind Advisory from 11 AM to 8 PM EDT Tuesday for KYZ044-050>052- 058>060-068-069-079-080-083>088-104-106>120. && $$ UPDATE...JMW SHORT TERM...GREIF LONG TERM...RAY AVIATION...JMW
Area Forecast Discussion
National Weather Service Louisville KY
1100 PM EDT Mon May 1 2017 .Forecast Update... Issued at 815 PM EDT Mon May 1 2017 Made some minor tweaks to precipitation coverage this evening as regional radars show light showers/sprinkles as far south as southern IL making their way toward the region. Otherwise, rest of forecast track, and will continue the wind advisory for eastern portions of the CWA through 03z as some sites are still gusting close to 40mph at this hour. && .Short Term...(This evening through Tuesday night) Issued at 252 PM EDT Mon May 1 2017 Surface analysis this afternoon showed a 993 mb low over central Wisconsin with its cold front now along crossing over the Appalachians. Large cyclonic flow extends across the lower Great Lakes and Ohio Valley. Satellite imagery shows extensive deck of strato-cumulus building in from the southwest, encompassing much of the forecast area. Efficient mixing this afternoon has brought down wind gusts 30 to 40 mph at times and temperatures range from the 50s and 60s in the clouds to low 70s across eastern Kentucky. In the near term, the main concern is wind gusts. Expect wind gusts of 35 to 40 mph at times through the evening hours across southern Indiana and central Kentucky. HRRR and RAP soundings show some of this better mixing continuing past 00z, especially along and east of I-65, so will extend the Wind Advisory through 03z for those areas, and let the western areas expire normally at 00z. Late this evening into the overnight, a piece of upper level energy will pivot across central Illinois in south central Indiana. This may bring isolated to scattered showers across southern Indiana and far northern Kentucky for a few hours, and will continue to mention 20-30 percent chances tonight. Plan on lows tonight in the upper 40s to low 50s with mostly cloudy skies. On Tuesday, the upper level low and surface become stacked over the Great Lakes which will bring another gusty day to the area. Soundings show efficient mixing up to 800 mb which will result in 35 to 45 mph wind gusts during the late morning and afternoon hours across much of the area. In coordination with JKL, will issue a Wind Advisory for the area from 11 am EDT to 8 pm EDT. Skies may start mostly sunny but there should be an extensive strato-cu deck by afternoon. Highs will top out in the 60s to low 70s. High pressure quickly builds in Tuesday night, and winds should quickly relax after sunset. Lows will be in the 40s, the coolest readings across the northern Bluegrass region where low 40s are expected. .Long Term...(Wednesday through Monday) Issued at 305 PM EDT Mon May 1 2017 The main theme in the long term is cooler than normal temperatures and potential for more unsettled weather later this week. Dry conditions are expected the first half of Wednesday but in a fast zonal flow, another weather system will quickly move east across the area by Wednesday afternoon. A low pressure system is forecast to track across northern Arkansas to western Tennessee. Showers and perhaps a few thunderstorms may spread into parts of the areas as early as Wednesday afternoon, but it appears the higher chances will come Wednesday night. The 05.01z models have converged on showing the surface and upper low deepening and becoming stacked over southern Illinois on Thursday, bringing more widespread showers to much of the area. Depending on exact timing of waves, there may be enough instability present in the afternoon for a few rounds of thunderstorms across central Kentucky. Will maintain the blended consensus for precipitation chances - 80 to 90 percent Thursday and Thursday night. Total rainfall Wednesday night through Friday is expected to be on the order of 1.5 to 2 inches. Some locally higher amounts are possible. For some areas, especially across southern Indiana and far northern Kentucky, this may be enough to cause some hydrology issues. Confidence in the forecast drops below average for Friday and the weekend as the upper level low is expected to be wobbling across the lower Ohio Valley. Models notoriously struggle with these solutions in the extended, and there is usually high run-to-run variance. Wrap around showers may persist into Friday and Saturday under colder, northwest flow. Unseasonably cool temperatures are possible Thursday and Friday if the cloudy and showery solutions do end verifying. Some of the raw gridded guidance has highs stuck in the 50s, but for now will use a blended approach which has highs in the low 60s Thursday and Saturday, but will stay in the 50s for Friday. The remainder of the long term looks to be under the influence of upper level troughing across much of the Great Lakes and mid- Atlantic. This should continue below normal temperatures and chances for showers at times. && .Aviation...(0Z TAF Update) Issued at 730 PM EDT Mon May 1 2017 VFR conditions are expected through the TAF period. Winds will be the main concern this TAF period as we remain on the south side of a strong low pressure system over the Great Lakes. WSW winds of 14-18 kts will continue to gust to 25-28 kts over the next 1-3 hrs. After sunset, winds will decrease some but gusts of 20-25 kts are still expected through much of the overnight hours. Also a sprinkle or two is possible in low clouds late this evening. We`ll see a brief lull in the breezy conditions and also a break in the mid cloud deck during the pre-dawn hours. However, by mid morning mid level clouds will build back in and WSW winds will pick up to 15-18 kts gusting to 25-28 kts again tomorrow. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...Wind Advisory from 11 AM EDT /10 AM CDT/ to 8 PM EDT /7 PM CDT/ Tuesday for INZ076>079-083-084-089>092. KY...Wind Advisory from 11 AM EDT /10 AM CDT/ to 8 PM EDT /7 PM CDT/ Tuesday for KYZ023>043-045>049-053>057-061>067-070>078-081- 082. && $$ Update...DM Short Term...ZT Long Term...ZT Aviation...AMS
Area Forecast Discussion...UPDATED
National Weather Service Miami FL
748 PM EDT Mon May 1 2017 .UPDATE... As of 745 PM EDT...Current forecast is largely on track with only minor updates based off the latest observations. Radar continues to depict convection weakening both in intensity and in spatial coverage this evening, with just some widely scattered showers and a few rumbles of thunder confined mainly to the interior. A few additional showers are also noted off Mainland Monroe County in the Gulf along with another streamer in the Atlantic. Will continue to maintain the mention of isolated to widely scattered showers through the night with the moist airmass in place and the frontal boundary in the Gulf inching closer to the region. Only major change for this update was to bump up PoPs late tonight over western areas, as the HRRR is now fairly aggressive in developing reinvigorated convection over the Gulf overnight. && .PREV DISCUSSION... /issued 730 PM EDT Mon May 1 2017/ AVIATION... Gusty southeast winds are already dying down and will continue the trend this evening. Overnight, expect SE wind 5-10 KT, increasing only slightly Tuesday. For Naples, effects of westerly Gulf Breeze will diminish after sunset, with SE winds returning overnight. Another Gulf breeze arrives at Naples midday Tuesday, turning winds WSW at around 10 knots. Showers today remained inland of terminals, and with only isolated activity expected through mid- morning Tuesday, kept TAFs dry through 15Z. Thereafter, scattered activity is forecast, and although isolated thunderstorm cant be ruled out, kept terminal forecasts with VCSH for now. PREV DISCUSSION... /issued 303 PM EDT Mon May 1 2017/ DISCUSSION... NEAR TERM /THROUGH 6 AM TUESDAY MORNING/... As of 300 PM EDT...South Florida continues to remain situated in a fairly humid and moist airmass ahead of a slowly approaching frontal boundary associated with low pressure in the Missouri River Valley. Dewpoints remain well into the upper 60s and lower 70s across most areas, with even a few mid 70s readings across far southern portions of the peninsula. These high dewpoints along with temperatures into the mid and upper 80s, and even some lower 90s in western interior areas, have yielded heat index values of lower 90s across many areas, quite warm and muggy for the first day of May. This warm and muggy airmass, aided by the formation of an enhanced southeasterly Atlantic sea breeze and weak Gulf sea breeze, has led to an active convective afternoon across interior areas of South Florida. An earlier streamer of showers stretching from the upper Keys into south-central Florida has given way to more numerous showers and embedded thunderstorms, now stretching into portions of the Gulf Coast and Lake Okeechobee region but still confined to interior areas. This trend will continue into the early evening hours, with local outflow and sea breeze convergence enhancing activity, some of which may be locally strong with brief gusty winds, frequent lightning, and brief heavy rainfall. Most of the activity will be confined to interior areas, but a few showers and perhaps a rumble of thunder cannot be ruled out for coastal areas either. Heading into tonight, ongoing convection will begin to rapidly diminish, with a northwesterly upper-level flow possibly bringing in one last round of scattered showers and storms into western portions of the east coast metro. For the rest of tonight, generally dry weather will prevail, although some showers and isolated storms will continue to be possible mainly over the Gulf waters. Winds over interior areas look to decouple and combined with recent rainfall, some patchy fog will be possible late tonight. Low temperatures will be mild, generally in the low to mid 70s. SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/... The aforementioned frontal boundary will continue to slowly approach the region on Tuesday, keeping the region in a moist flow regime. With the front and associated forcing slightly closer to the region, along with hints of possible shortwave energy swinging by to the north, another active convective day will ensue on Tuesday. Coverage looks to be greater than today, with scattered to numerous showers and thunderstorms possible across much of mainland. Heavy rain and lightning will be the primary threats with thunderstorms, but cannot rule out some brief gusty winds with the strongest storms as well. While most areas will dry out some Tuesday night, widely scattered showers will continue to linger into the overnight hours as the front begins to stall just northwest of the region. On Wednesday, the frontal boundary will begin to decay as its parent storm system lifts well to the north into southern Canada. With less of a synoptic forcing influence, mesoscale features will dominate with the Gulf and Atlantic sea breezes being the primary forcing mechanisms. Plenty of remnant moisture and instability will remain present to promote another day of diurnally-driven scattered showers and storms mainly across interior and western areas. Rainfall on both Tuesday and Wednesday is much welcomed and needed across portions of South Florida continuing to deal with moderate to severe drought conditions. Temperatures in the short term period will continue to be warm for early May standards, with highs into the mid and upper 80s on Tuesday, although not as warm as today with more convection expected, and Wednesday mid 80s to lower 90s. Lows will be in the upper 60s to mid 70s. LONG TERM /THURSDAY THROUGH SUNDAY/... An active northern stream pattern across much of the CONUS looks to continue into the long term period, as both the GFS and ECMWF prog a deep longwave trough eventually becoming cutoff from the flow across the lower Great Lakes region. This system will swing a trailing cold front across the region, with both models continuing to show fairly decent consensus in the passage occurring sometime late Thursday into Friday. Will need to continue to monitor timing trends in the long range guidance, as cutoff lows can produce high amounts of uncertainty 5 days out. An increase in shower and thunderstorm coverage will accompany the frontal passage, but it is still too early to get into any specifics with heavy rain and/or strong thunderstorm potential. Behind the frontal passage, high pressure looks to build into the region from the north, ushering in a much drier airmass compared to the previous week. At this time, dewpoints look to plummet into the 50s across much of the region for the weekend and ending the humid conditions at least temporarily. Temperatures throughout the long term period will be near to slightly above average. MARINE... Outside of brisk southeast winds of 15-20 knots creating exercise caution levels for the Atlantic waters through tonight, generally good boating conditions are expected to prevail across the local waters through midweek. Outside of local sea breeze effects, the flow will generally be southeasterly on Tuesday and east/northeasterly on Wednesday at less than 15 knots. Seas will be 4 feet or less over the next few days. Isolated showers, and perhaps a thunderstorm or two, will be possible especially in vicinity of both coasts. An approaching frontal boundary late in the week will bring an increasing threat for showers and thunderstorms to the local waters. BEACH FORECAST... A High Risk of rip currents will continue to remain in effect for the Atlantic beaches through early Tuesday morning with continued brisk southeast onshore flow. Decreasing winds, outside of local sea breeze effects, will help to reduce the rip current risk for the Atlantic beaches Tuesday, but remnant wave energy and coastal resettling will pose at least a Moderate Risk for rips during the day Tuesday. Rip current risk looks to continue gradually diminishing heading into Wednesday as well. FIRE WEATHER... No significant fire weather concerns are anticipated through at least Friday, with relative humidity expected to remain above critical levels along with chances for showers and thunderstorms. Behind a frontal passage Friday, a much drier airmass will be ushered into the region, with relative humidity values possibly dipping well below 40 percent, and will continued to be closely monitored over the coming days. && .PRELIMINARY POINT TEMPS/POPS... West Palm Beach 74 86 72 86 / 20 50 20 20 Fort Lauderdale 75 85 74 85 / 20 50 20 20 Miami 75 86 74 87 / 20 40 20 10 Naples 73 86 71 88 / 30 40 20 30 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...High Rip Current Risk through Tuesday morning for FLZ168-172-173. AM...None. GM...None. && UPDATE...92/IRL DISCUSSION...92/IRL MARINE...92/IRL AVIATION...23/SK BEACH FORECAST...92/IRL FIRE WEATHER...92/IRL