####018009133#### FXUS61 KOKX 162015 AFDOKX Area Forecast Discussion National Weather Service New York NY 415 PM EDT Fri May 16 2025 .SYNOPSIS... A warm front draped over portions of the Mid Atlantic lifts north through the region tonight into early Saturday. An attendant cold front follows, with the passage expected Saturday evening. A secondary cold front passes Sunday night. Low pressure lingers in New England and the Canadian Maritimes Sunday through Monday. High pressure takes control Monday night into early Tuesday night. Another frontal system impacts the area Wednesday into Thursday. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... Digging trough and upper low over the Upper Midwest swings east across the Great Lakes region, sending an associated frontal system toward the region. Warm front analyzed to the southwest over the Mid Atlantic begins to approach and lift through tonight. Remnant MCS that had been advancing east through Pennsylvania has weakened substantially as it reached the local region, with only a few lingering showers over parts of LI late this afternoon. Largely dry conditions expected thru the remainder of the day, with perhaps a few isolated showers popping up as forcing and instability remain weak with the boundary still to the south, and parent low well off to the west. With multiple spokes of vorticity rounding the trough, CAMs have been signaling another MCS potentially developing well to the west along the boundary tonight, before working east with the outflow. Should this occur, it's possible the remnants work into the region overnight, though this is far from a guarantee, and any local severe risk from this potential activity is low. Otherwise, likely see areas of fog development once again into the night with light flow and abundant surface moisture. The fog may become locally dense depending on the evolution of any convective system(s) to the west. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/... Upper level low and trough over the Great Lakes pivots east on Saturday, as a vigorous shortwave tracks across the Mid Atlantic. A warm front lifts thru by the morning, as the associated surface low slides into Quebec. The attendant cold front looks to move through locally in the early to mid evening. A challenging convective forecast with uncertainty on timing and coverage of any morning activity. The approaching cold front adds more in the way of forcing as the day progresses, and breaks in the clouds should develop by the afternoon. 12z HREF is progging MLCAPE values as high as 1500 J/kg, along with bulk shear values 30 to 40 kt. That said, cloud cover could limit this instability, and subsidence behind any previous MCS could help to cap the low levels as well. It now appears the core of the shortwave energy passes north and west by mid afternoon, and could help limit any organized severe threat locally. With this, SPC has lowered their threat locally from a slight to a marginal, which seems reasonable based on the above and continued uncertainty. CAMs aren't overly aggressive in depicting convective development, but should initiation occur, damaging wind gusts would be the primary threat, though large hail and even an isolated tornado cannot be ruled out in the environment. Coverage looks isolated to scattered, especially across the LoHud Valley and southern CT. Cold frontal passage progged around 00Z Sun, and behind it winds veer westerly into the overnight, with drying conditions overnight as dew pts fall back into the lower 50s by daybreak. && .LONG TERM /SUNDAY THROUGH FRIDAY/... Key Messages: * Mainly quiet & pleasant weather Sunday through Tuesday. * A frontal system may will bring rainfall Wednesday, possibly into Thursday and Friday. A surface low w/ an associated upper-level low will be located over New England Sunday. This low will exit into the Canadian Maritimes by Monday. This low will bring a second cold front through on Sunday night helping clear out partly to mostly cloud skies and advecting in drier air. This leaves late Sunday night into Monday mostly clear/sunny. A few showers are possible in the northern interior, closer to the periphery of the low Sunday afternoon/evening, but chances look quite low. A quick moving shortwave will pass over or just to the north of the area Monday afternoon/evening. This may lead to a few clouds, but otherwise, we will remain clear and sunny late Sunday night through most of Tuesday. An increased pressure gradient from the low to our northeast will lead to breezy W/NW flow Sunday and Monday. As the low exits farther away, the gradient weakens, leaving light winds by Monday night. It remains this way with high pressure at the surface through Tuesday. 12Z guidance still varies in timing and track of a frontal system for the middle of next week. A low over TN/KY late Tuesday will approach the area Tuesday night and pass near or to the south of the area Wednesday into Thursday, pushing more north and/or east of the area on Friday. This will bring a period of wet weather. There is higher confidence in showers on Wednesday, but confidence is lower Thursday and especially Friday and models diverge on a solution. Sunday and Monday will see highs in the upper-60s to mid-70s, right around the climatological average. Temperatures will be much cooler from a passing frontal system on Wednesday with highs in the low-60s under E/NE flow. && .AVIATION /20Z FRIDAY THROUGH WEDNESDAY/... Weak low pressure with a surface trough near the area today, followed by a warm front moving through Saturday. Cold front follows for Saturday evening. Mainly dry conditions expected through early this evening. Potentially 3 additional rounds of rainfall in the TAF period. Next one is coming up late this evening into overnight, just mainly showers within and around NYC terminals with VCSH in TAFs. Next round after that is Saturday morning but too low confidence to include in TAFs. After that is Saturday afternoon into early Saturday evening which is when showers and thunderstorms will be possible with PROB30s in the 30 hour TAF sites. Outside of some brief VFR early this evening and late in the TAF period, mainly IFR to LIFR conditions expected. Some coastal sites already have redeveloped IFR stratus this afternoon. LIFR expected overnight into Saturday morning with clouds lowering and fog forming. Category forecast is of low confidence with amendments likely. There could be fluctuation between categories during the TAF period. Southerly flow near 5-10 kts expected through much of the TAF period. Southerly winds pick up to near 10-15 kt with some gusts up to 20 kt Saturday afternoon. ...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty... Timing of IFR, MVFR, and LIFR changes could be a few hours off from TAF. VLIFR possible early Saturday, 08-12Z. .OUTLOOK FOR 18Z SATURDAY THROUGH WEDNESDAY... Saturday: Mainly VFR but MVFR possible in the afternoon with chance of showers and thunderstorms with MVFR or lower conditions possible. Sunday: Mainly VFR. Slight chance of showers inland with MVFR possible. W winds G20-25kt. Monday - Tuesday: VFR. Monday NW winds G20-25kt day into evening. Wednesday: MVFR or lower with showers likely, mainly at night. E wind gusts 15-20 kt. Detailed information, including hourly TAF wind component forecasts, can be found at: https:/www.weather.gov/zny/n90 && .MARINE... Areas of fog likely return tonight, potentially becoming dense and persisting into mid Saturday morning. A Dense Fog Advisory may be needed, with the potential for vsbys to fall to less than 1 nm at times overnight into Saturday AM. Winds and waves remain below Small Craft Advisory (SCA) criteria through at least Saturday night. Sunday afternoon and evening, wind gusts may marginally reach SCA criteria for the NY Harbor, western Sound and western Ocean. Otherwise, sub SCA conditions are expected on all waters thereafter through Wednesday. A passing frontal system will lead to ocean seas climbing 5-7 feet Wednesday night through Thursday night. && .HYDROLOGY... Locally heavy downpours are possible with any thunderstorms through Saturday aft/eve. While the overall flash flood threat is low, the brief heavy rainfall could lead to minor nuisance flooding in urban and poor drainage areas. There are no other hydrologic concerns through the end of next week. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...None. && $$ SYNOPSIS...BR/DR NEAR TERM...DR SHORT TERM...DR LONG TERM...BR AVIATION...JM MARINE...BR/DR HYDROLOGY...BR/DR ####018003631#### FXUS63 KARX 162018 AFDARX Area Forecast Discussion National Weather Service La Crosse WI 318 PM CDT Fri May 16 2025 .KEY MESSAGES... - Scattered to numerous showers from this afternoon into tonight and isolated to scattered showers Saturday. There maybe an isolated storm from southwest into central Wisconsin this afternoon and early evening. Rainfall totals will be up to a tenth of an inch. - More rain expected Monday into Wednesday. Highest totals (1-1.5 inches) along and south of Interstate 90. In northeast Iowa, there is a 20-45% chance that the rain may exceed 2 inches. && .DISCUSSION... Issued at 318 PM CDT Fri May 16 2025 Tonight into Saturday A closed 500 mb low will produce scattered to numerous showers as it moves east southeast from northern Minnesota east into southern Lower Michigan. With the best instability (500-1500 J/kg) east of the area, not anticipating many thunderstorms in our area. If there is one, it would be in southwest and central Wisconsin. Rainfall amounts will be mainly less than a tenth of an inch. Considered issuing a Wind Advisory west of the Mississippi River, but model soundings show that the mixing depths will continue to decrease throughout the afternoon. As this occur, the ability to tap into the higher winds aloft will decrease. Monday into Wednesday A closed low pressure area will move east from eastern Nebraska and southeast South Dakota east into the southern Great Lakes. Meanwhile, north of this low, there will be a 500 mb ridge located the north and northeast of this low. Dry easterly winds on the south and southwest periphery of this high will continue to advect dry air into parts of the forecast area. This will result in a distinct northern extent of this rain. There is still some uncertainty on where this will occur. When compared to yesterday, the rain has shifted slightly further north. While this was the case, the 50th percentile of the precipitable water vapor has remained stay near 1 inch. At this time, rain totals will likely range from a 0.5 to 1 inch north of Interstate 94 and 1 to 1.5 inches elsewhere. In northeast Iowa, there is a 20-45% chance that the rain may exceed 2 inches. It continues to look like the higher instability and shear will remain just south of the forecast area. As a result not anticipating severe weather at this time. && .AVIATION /18Z TAFS THROUGH 18Z SATURDAY/... Issued at 1246 PM CDT Fri May 16 2025 VFR conditions currently present at the terminals. A band of showers rotating around a surface low in west central Minnesota is currently moving through southern Minnesota and will approach the RST terminal in the coming hours. Showers will become more widespread through the evening hours so have gone with prevailing groups at the terminals. In conjunction with the rain, ceilings are also expected to drop. MVFR ceilings will move in from the west after 21Z with IFR moving into the RST terminal a little before 06Z. Did not have enough confidence to put an IFR prevailing group for LSE so have gone with a PROB30 for now. Showers will gradually end between 06-12Z with better chances moving into West Central Wisconsin. Winds will remain gusty through the period starting out of the west/southwest, becoming more northeasterly by tomorrow morning. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None. && $$ DISCUSSION...Boyne AVIATION...Barendse ####018008875#### FXUS63 KIND 162019 AFDIND Area Forecast Discussion National Weather Service Indianapolis IN 419 PM EDT Fri May 16 2025 .KEY MESSAGES... - Severe Thunderstorms are expected between 5-11PM EDT. - All Severe modes are in play today, including damaging straight line winds, large hail, and tornadoes. The greatest threat looks to be widespread damaging winds south of the I-70 corridor - Warm and humid with highs in the mid to upper 80s. - Cooler and quiet for the weekend, additional precipitation again next week && .MESOSCALE UPDATE... Issued at 419 PM EDT Fri May 16 2025 SURFACE ANALYSIS SHOWS STRONG PRESSURE FALLS OVER THE MID-MS VALLEY REGION FROM JUST EAST OF THE QUAD CITIES DOWN INTO EASTERN IL. ALTHOUGH MOISTURE RETURN HAS BEEN SOMEWHAT SLOW THIS AFTERNOON, THE INCREASING PRESSURE FALLS AND LATEST TRENDS INDICATE A MORE RAPID NORTHWARD DEVELOPMENT OF THE DEEPER MOISTURE WITH DEWPTS IN THE LOWER 70S ACROSS SOUTHERN IL/FAR SW INDIANA. THE LEADING EDGE OF THE DEEPER MOISTURE IS ALSO EVIDENT BY THE LEADING EDGE OF AN AGITATED CUMULUS FIELD NOTED ON VISIBLE SATELLITE, EXTREME INSTABILITY WITH MLCAPE VALUES FROM 3500-4500 J/KG EXISTS OVER SOUTHERN INDIANA WITH THESE CONDITIONS DEVELOPING NORTHWARD INTO CENTRAL INDIANA OVER THE NEXT 2-4 HRS. IN ADDITION, THE AREA OF ENHANCED PRESSURE FALLS IS COINCIDENT WITH LOCALIZED BACKING OF THE SURFACE WIND FIELDS WITH RECENT 0-1KM SRH NEAR 200 M2/S2 AROUND THE ST. LOUIS AREA WHICH WILL ALSO DEVELOP NORTHWARD INTO CENTRAL IN. THE CLUSTER/BROKEN LINE OF SEVERE THUNDERSTORMS SOME EXHIBITING SIGNIFICANT ROTATION /INCLUDING A CONFIRMED DAMAGING TORNADO IN ST.LOUIS IN THE LAST 30 MINS/ WILL CONTINUE TO MOVE E-NE 40-50 KTS AND ENTER FAR WESTERN INDIANA AROUND 22Z AND MOVE INTO THE INDY METRO AREA AROUND 2300-2330Z. THE KINEMATIC ENVIRONMENT WILL CONTINUE TO FAVOR A THREAT FOR TORNADOES, SOME POSSIBLY SIGNIFICANT, WITH ANY STORMS THAT CAN REMAIN DISCRETE OR SEMI- DISCRETE. IN ADDITION THE THREAT FOR LARGE HAIL GREATER THAN 2 INCHES IN DIAMETER AND DOWNBURST WIND GUSTS OVER 70 MPH WILL CONTINUE WITH THE MOST INTENSE STORMS. && .SHORT TERM (This afternoon through Saturday)... Issued at 1152 AM EDT Fri May 16 2025 Update for upcoming severe event: Key Messages: - Widespread thunderstorms with numerous severe thunderstorms expected between 5PM and 11PM EDT - All severe weather hazards possible, but highest confidence in destructive wind gusts. Most intense gusts could be greater than 80mph - Long track supercells are possible over far southern central IN. Within these supercells, significant tornadoes are possible. Discussion: There is a growing concern for a localized severe weather outbreak over central Indiana late this afternoon and evening. Satellite and radar imagery depict numerous elevated thunderstorms with widespread rain and anvil cirrus over KY currently, of which many of the near term models have struggled to materialize. This could create some uncertainty on overall storm track this evening as even with modest moisture advection it will take some time for this area to recover. The current expectation is for this to result in a CAPE gradient across the southern portions of Indiana, further solidifying the development of robust convection this afternoon and evening. Current observations show most of central Indiana already in the mid to upper 70s with dew points near 60. There will likely be some low level mixing this afternoon that will continue to drop dew points into the upper 50s, especially north of I-70 prior to convective initiation. However further south, greater SW moisture advection and some anvil cirrus should keep low level dew points elevated, with dew points in the mid 60s prior to convective initiation. This will result in quick destabilization with widespread CAPE values greater than 2500 J/kg south of I-70. As the pressure trough pushes eastward, modest lift will be sufficient enough for explosive initiation across IL, of which is expected to reach the Indiana border between 4:30 and 6:00 PM EDT. Further analysis of the low level thermodynamics shows very steep 0- 5km lapse rates, averaging around 8 C/km. The 5km layer winds will generally be around 50kts, increasing this evening to 70-80kts. Given the steep lapse rates, and dry mid level air, dense and volatile cold pools are likely to develop within organized storms. These cold pools will be capable of producing isolated wind gusts greater than 90 MPH, but numerous 60 MPH wind gusts are likely south of the I-70 corridor. This same set up also is favorable for significant hail, although this threat will slowly wane as the convection become more linear this evening. Greatest winds are likely to be south of the I-70 corridor where the LLJ axis is centered, but scattered severe wind gusts are still possible north of I-70. There is also a tornado threat with these storms this afternoon and evening primarily south of I-70. Given residual capping over southern IN from the previously mention thunderstorms over KY this morning, along with a more favorable shear vector, some discrete convection is possible in the beginning of the severe thunderstorm threat (5-8PM). Modeled soundings currently show 0-3km SRH greater that 300 m2/s2 in this same region, of which is plenty sufficient for mesocyclone development and therefore supercells. Although LCLs are likely to be slightly elevated initially, very steep near surface lapse rates along with 0-1km SRH of 100-200 m2/s2 should be enough to overcome as the mesocyclones strengthen and become more mature. 7PM onwards the LLJ is also likely to increase further intensifying the low level shear. The main uncertainty with long track supercells will be how quickly organized convection grows upscale and becomes linear. Outside of supercell tornadoes, there is a QLCS tornado threat as these storms develop strong cold pools. If a tornado does happen north of I-70, this will likely be the storm mode. Given the aforementioned likelihood of robust cold pools and RIJ, there will likely be surges within any linear feature. These surges in the presence of strong LL shear this evening will likely be sufficient for a few embedded tornadoes within lines. && .LONG TERM (Saturday through Thursday)... Issued at 307 AM EDT Fri May 16 2025 An exiting low will move off to the NE at the start of the period. Behind the low, broad riding across the central plains will initially dominate this weekend. Pressure gradients between the system will keep wind gusts to around 25-30 mph during the afternoon on Saturday but will be much calmer for Sunday. A more active pattern is then expected for much of the work week as an upper low, with a couple of short wave, moves through the region. Models are struggling to determine the details at this time as different solutions show varying tracks and strengths to the system. Confidence on temperatures is also low as it will depend on what side of the low central Indiana ends up with. Despite the uncertainties, it does look like there will be a good amount of moisture to work with, so could see a threat for multiple days of heavy rain, and temperatures probably below normal for much of the week. Towards the end of the long term and into the holiday weekend, a ridging pattern may set up to bring from the rain expected next week, but it is still too soon to have much confidence in this yet. && .AVIATION (18Z TAF Issuance)... Issued at 131 PM EDT Fri May 16 2025 Impacts: - High confidence for evening thunderstorms, possibly severe Discussion: VFR conditions expected through 21Z today. Thunderstorms will push through from west to east after with first impacts at KHUF. Generally, ceilings should remain above 3000 within thunderstorms, but brief reductions to MVFR are possible. Within thunderstorms gusts to 50 or greater knots are possible. Coverage of thunderstorms should diminish quickly after 00Z at KHUF and 02Z at KIND and KBMG. Thunderstorms threat is expected to be completely over by 05Z. Outside of thunderstorms gusty S to SW winds are expected to around 20kts. Winds will shift towards westerly after thunderstorms pass overnight but should remain above 10kts through a majority of the period. && .IND WATCHES/WARNINGS/ADVISORIES... None. && $$ MESOSCALE...Crosbie SHORT TERM...Updike LONG TERM...Updike AVIATION...Updike