####018006796#### FXUS61 KRNK 130706 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 306 AM EDT Mon May 13 2024 .SYNOPSIS... High pressure will move off the coast this evening. A warm front lifts north through the southeast Tuesday followed by a cold front Wednesday. This will bring periods of showers and a few thunderstorms to the area. High pressure arrives briefly Thursday before another low pressure system tracks in from the lower Mississippi Valley Friday. && .NEAR TERM /THROUGH TONIGHT/... As of 244 AM EDT Monday... Key Messages: 1) Dry with increasing high clouds today. 2) Rain moves in late tonight. Dry weather today as high pressure heads offshore. Already seeing some thin cirrus starting to move across our area early this morning, and during the day, the high clouds will become more opaque blotting out the sunshine at times. Still enough solar insolation to bring high temperatures to at or slightly above normal with most in the 70s. Tonight, upper trough tracks into the lower MS Valley with southwest flow aloft over our area. Warm front in place across the Gulf Coast states, will send moisture up along the mountains/foothills of NC by late evening then surging through the rest of the area by Tue morning. Showing some good isentropic lift along the 300-305K surfaces overnight. Getting some model differences as to placement of best lift/qpf. Leaning toward along/east of the Blue Ridge with the higher pops but most of the area will see at least a 70+ percent chance of having measurable rain by dawn, but generally less than a quarter of an inch, with up to half inch possible along the southern Blue Ridge into the NC foothills. Airmass will likely be stable to prevent any thunderstorms late tonight. With cloud cover and warm advection lows tonight will be milder with 50s areawide. Forecast confidence is greatest on temperatures and sky cover/wind, and average on qpf/pops overnight. && .SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/... As of 245 AM EDT Monday... Key Messages: 1. Showers and storms possible Tuesday. 2. Dry weather returns Thursday. 3. Near normal temperatures through midweek. A surface low pressure system approaches the area from the west Tuesday, and high pressure moves offshore. Broad southerly flow at the surface and southwesterly flow aloft will draw moisture into the area from the Atlantic and Gulf of Mexico, and rain showers will become more widespread Tuesday. The warm front lifts northward and the surface low tracks closer to the area Tuesday, and instability will increase the chances for thunderstorm development, with the greater probabilities for storms in the west, closer to the surface low. However, thinking ample cloud cover throughout the day will limit daytime heating, and thus limit the potential for storms to become severe. Rainfall amounts through Wednesday are between three quarters of an inch to just about an inch and half. Locally heavy rainfall is possible from this system, as precipitable water values exceed the 90th percentile relative to climatology Tuesday into Wednesday, so there is potential for localized flash flooding, especially in areas that have received recent rainfall. Shower and storm chances continue into Wednesday, as moisture wraps around the low as it tracks through the Mid Atlantic. By early Thursday morning, 500mb ridging builds back into the area, in response to another trough deepening over the Rockies and western US. A drier airmass fills into the area behind the front, reducing shower and storm coverage for Thursday. Temperatures will generally be near normal for this forecast period, cloud cover keeping overnight lows on the mild side, in the 50s and 60s. High temperatures will gradually warm through the period, with Thursday looking to be the warmest day, highs near 80 in the Piedmont, and in the low to mid 70s in the west. && .LONG TERM /FRIDAY THROUGH SUNDAY/... As of 230 AM EDT Monday... Key Messages: 1. Showers and storms possible again Friday, lingering into the weekend. 2. Near to slightly above normal temperatures. Mid level ridging will slide east of the area through Friday, with flow aloft turning more southwesterly. Another surface low pressure will approach the area from the west, bringing the next chance for widespread showers and thunderstorms. As noted in the previous discussion regarding this system, deterministic models continue to show differences in timing and placement of the heaviest precipitation from this system, with some suggesting greater precipitation to the north and to the south of area, and others showing a broad axis of heavy rain across much of the eastern US, although better agreement in showers reaching the area by at least Friday afternoon and continuing into Saturday. That being said, confidence is lower in the forecast for the end of the workweek. Thinking the potential for storms Friday is lower than the middle of the week system, since the upper trough is not quite as strong, the base of the ridge farther north of the area compared to the Tuesday system. Upper ridging and surface high pressure move back into the eastern US by Sunday as the low moves off the coast, decreasing coverage of any lingering precipitation. Sunday looks to be the warmest day of this forecast period, with high pressure overhead. Cloud cover and rain will keep Friday and Saturday cooler, but generally temperatures will be near normal. && .AVIATION /07Z MONDAY THROUGH FRIDAY/... As of 105 AM EDT Monday... Going to be VFR through 06z/Tue. Anticipate increasing high clouds today, lowering to a mid deck by the end of the period. Could see some low end VFR ceilings possibly getting toward BCB/DAN but most of the sub-VFR will be after 06z/Tue. A light/calm wind this morning will be coming from the south at 5-10kts by 15-17z Monday. High confidence this forecast period. Extended Aviation Outlook... Rain showers and sub-VFR ceilings and visibilities return to the region late Monday night through midweek, through sub-VFR will not occur all the time. Thursday should return to VFR most areas with some lingering MVFR possible in the mountains. More sub- VFR likely Friday with another storm system with showers/storms. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...WP NEAR TERM...WP SHORT TERM...AS LONG TERM...AS AVIATION...WP ####018004402#### FXUS63 KGRR 130707 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 307 AM EDT Mon May 13 2024 .KEY MESSAGES... - Shower and Thunderstorm Chances Today into Tuesday - Drying Out Midweek - Periodic Risk for Rain Thursday Night into the Weekend && .DISCUSSION... Issued at 244 AM EDT Mon May 13 2024 - Shower and Thunderstorm Chances Today into Tuesday A few lingering light showers this morning to exit to the east prior to daybreak with a dry start expected this morning. Stalled out front near I-96 to provide the focus mechanism for increasing shower and thunderstorm potential mid to late this afternoon. Severe weather is not expected. Coverage of showers/storms should be near I-96 and south with northern areas remaining mostly dry. Initial shower/storm development will be more scattered in coverage before a transition toward a more widespread steady rain occurs late tonight into early Tuesday. Some locations could see over an inch of rain over the next 24 hours or so. High pressure slowly building in will begin to dry things out Tuesday afternoon. Prior to onset of showers later today, temperatures will warm up nicely with mid to upper 70s for most with a non zero chance of a few locations topping out at or above 80 degrees. - Drying Out Midweek Modest mid level height rises and dry surface to 850 mb northeasterly flow is expected for the midweek period beginning Tuesday night and lasting through Wednesday. Low and mid level flow veers southwest by Thursday out ahead of the next system slated to impact the region by week's end. But the majority of Thursday is likely to remain dry as well at this point. - Periodic Risk for Rain Thursday Night into the Weekend Currently, the most likely period for rain is Thursday night into Friday. Uncertainty exists regarding the synoptic pattern for the weekend. For Late Thursday into Friday, an upper trough is forecast to move through. Upper jet divergence is favored for our region. A weak LLJ is shown to nose into the southern portion of Michigan, especially by the 00z GFS and GEM. ECE and GEFS ensemble guidance suggests PWATs rising into the 1.00"-1.25" range. With synoptic scale lift, increasing moisture, and marginal elevated (and potentially some surface based) instability present, showers and thunderstorms remain in the forecast mainly from Thursday evening/night into Friday. POPs are around 50% but likely trending up as we get closer, once medium range guidance pins down the timing. Following this system, much depends on how strong the upper ridging gets over the upper Midwest and Great Lakes, and whether a renewed LLJ develops an orientation that brings in low level moisture and forcing to the region. Various model solutions exist over the weekend, leading to low confidence in the synoptic pattern evolution. Ensemble guidance 50th percentile 24hr QPF currently favors little in the way of rainfall, but several individual ensemble members have some significant rain amounts over an inch. With convectively driven precipitation, that is to be expected this far out. NBM POPs of around 30% for the weekend look good. Highs in the 70s are favored at this time. && .AVIATION /06Z TAFS THROUGH 06Z TUESDAY/... Issued at 120 AM EDT Mon May 13 2024 Showers and a few thunderstorms have occurred across the region during the early morning hours. The expectation is for any thunderstorms to be moving out of the region by 07z or so. But some showers may remain. Low level wind shear is likely to continue through mid morning before diminishing. A wider coverage of showers will likely move in toward late afternoon or evening, and some thunderstorms will also be possible. No VCTS mention yet, but possible inclusion may be featured with time. && .MARINE... Issued at 244 AM EDT Mon May 13 2024 Lighter winds expected today and much of tonight before an increase in winds occurs closer to Tuesday morning. Small Craft Advisory still looking likely beginning early Tuesday. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. MARINE...None. && $$ DISCUSSION...Maczko/Hoving AVIATION...Hoving MARINE...Maczko ####018003408#### FXUS62 KTBW 130707 AFDTBW Area Forecast Discussion National Weather Service Tampa Bay Ruskin FL 307 AM EDT Mon May 13 2024 ...New DISCUSSION, AVIATION, MARINE, FIRE WEATHER... .DISCUSSION... Issued at 301 AM EDT Mon May 13 2024 The work week will start out quite a bit more humid compared to yesterday as deeper moisture returns. As the high pressure moves further over the Atlantic the flow becomes more S/SE and winds increase as the gradient tightens. Rain chances also increase tomorrow as the sea breezes collide along the interior. Some storms developing along these boundaries could become severe as extra energy provided by mid-level impulses move over the area, supporting elevated CAPE values and effective bulk shear. With all these ingredients coming together, Storm prediction Center has placed portions of our CWA in a marginal risk for severe weather this afternoon. Main concern will be along the nature coast and the interior where sea breeze collisions are expected. Main threat will be for hail, damaging wind gusts and a possible tornado. Tuesday into Wednesday, a shortwave trough moves east scraping across northern portions of the peninsula. A surface low with accompanying this short wave is expected to move over the area bringing another round of showers and storms. SPC has also marked areas mainly north of I4 as a marginal risk for severe thunderstorms, Tuesday and portions of Levy county and areas northward, Wednesday. Conditions begin to dry out Thursday into Friday as ridging tries to build back over the area. Temperatures remain on the above average side, with highs in the low to mid 90s more most areas. && .AVIATION... (06Z TAFS) Issued at 301 AM EDT Mon May 13 2024 Vfr conditions prevail. SE winds will begin to increase and move onshore by the afternoon. Some afternoon convection is likely, but will likely occur inland, away form most terminals, except maybe LAL. Tuesday into Wednesday more showers and thunderstorms are possible, especially for areas north of I4 and inland. && .MARINE... Issued at 301 AM EDT Mon May 13 2024 Pressure gradient tightens today allowing for increased SE winds that will turn onshore as the sea breeze develops. Scattered showers and thunderstorms will move into northern waters beginning tonight with another round likely tomorrow into Wednesday. Increased winds will also support increased wave heights. Unfavorable marine conditions will likely last until the end of the week. && .FIRE WEATHER... Issued at 301 AM EDT Mon May 13 2024 No major fire weather concerns through the week as RH values remain above critical levels. Shower and thunderstorms are expected to move over portions of the CWA beginning tonight and continuing through Wednesday. && .PRELIMINARY POINT TEMPS/POPS... TPA 92 78 90 79 / 30 30 30 40 FMY 95 77 94 79 / 20 10 10 10 GIF 93 74 95 76 / 50 30 40 30 SRQ 93 77 91 77 / 20 10 20 30 BKV 94 70 93 73 / 40 30 50 50 SPG 90 80 89 80 / 20 20 30 40 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...None. Gulf waters...None. && $$ DISCUSSION/AVIATION/MARINE/FIRE WEATHER...Pearce DECISION SUPPORT...Close ####018002905#### FXUS63 KUNR 130708 AFDUNR Area Forecast Discussion For Western SD and Northeastern WY National Weather Service Rapid City SD 108 AM MDT Mon May 13 2024 .KEY MESSAGES... -Unsettled this week with periodic chances for showers and thunderstorms, best chances late tonight into Tuesday. -Smoke from Canadian forest fires will slowly push SE out of the region and diminish today, although it will likely return later in the week. -Seasonally temps most of the week. && .DISCUSSION...(Today Through Sunday) Issued at 105 AM MDT Mon May 13 2024 Mean NW flow can be expected through the week, supporting occasional weak PAC impulses. Each of these impulses will have the ability to support isold-sct shra/ts as a frontal boundary wavers over the region. Moisture will continue to be limited with most of the impulses as the GOMEX remains closed to the region, leaving the main moisture source as leftover PAC moisture. Slow moving upper trough will support increasing LSA with mid level moisture adv across the region today. This will bring increasing low chances for showers/storms across the western third, starting first over the Black Hills, then across NE WY. CAPE and shear remain highly limited with severe weather not expected. As the upper trough shifts east overnight, pos theta-e adv will support shower chances across the FA, esp the NW third closest to the best LSA. Shower chances will shift SE through the day Tues, with NW winds increasing behind the sfc cool front, possibly bringing more smoke to the region. Unsettled NW flow will persist through the remainder of the week with chances for showers each day. Things trend drier later in the week, with continued low chances for showers each day. Expect most areas will remain dry toward the end of the week, with more isolated convection. Overall, temps will be seasonal with highs generally in the 70s, with Tue-Wed being the coolest days, given weak CAA and lingering shower chances. Overall, any appreciable rain will be localized with most places seeing a few hundredths or less given lack of deep moisture and convective nature of precip. && .AVIATION...(For the 06Z TAFS Through 06Z Monday Night) Issued At 1043 PM MDT Sun May 12 2024 Wildfire smoke filtering into the region may cause periods of MVFR visibilities this morning, mainly across western to central South Dakota. Isolated to scattered thunderstorms will redevelop Monday afternoon and push eastward across the area Monday night. Lower flight conditions and erratic and gusty winds are possible near any storms. Otherwise, VFR conditions are expected through the TAF period. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...None. WY...None. && $$ DISCUSSION/KEY MESSAGES...JC AVIATION...13