####018004698#### FXPQ50 PGUM 160751 AFDGUM Area Forecast Discussion National Weather Service Tiyan GU 551 PM ChST Fri May 16 2025 .Marianas Synopsis... Partly cloudy skies with isolated showers and gentle to moderate trade winds reign over the region this afternoon. Buoys and altimetry data show seas between 4 and 6 feet. && .Discussion... No major changes were made to the forecast. A dry trade-wind pattern remains firmly intact across the Marianas. CIMMS MIMIC suggests the Marianas has about 1.6 to 1.9 inches of Precipitable WATer (PWATs). This is higher PWATs than previous weeks. Time heights also confirm a deepening moisture layer, especially in the upper atmosphere and the mid atmosphere by end of next week. These are the first signs that the transition to wet season may be starting. && .Marine... Combined seas of 4 to 6 feet will keep marine conditions fairly benign. Winds are expected to remain moderate through next week. A moderate risk of rip currents remains along east facing reefs, with a low risk along all other reefs. && .Fire weather... A trace of rain fell so far today at the Guam International Airport. The KBDI remains at 745, which is in the high category due to winds remaining below the 20 mph threshold. Both winds and relative humidity values look to remain below Red Flag Warning criteria the next few days. A wetting rain is not expected for at least the next several days, and the KBDI is expected to continue to rise. && .Eastern Micronesia... A generally wet pattern produced by the ITCZ building overhead, is expected to last for at least the next several days. A peak in convective activity is expected over Pohnpei, with numerous heavy showers, isolated thunderstorms and strong gusts expected Saturday, with a slow taper down in shower coverage into early next week. Patchy on-and-off showers are expected at Kosrae and Majuro for much of the forecast period, with low-end scattered showers potentially as early as Monday night. Combined seas of 5 to 7 feet near Pohnpei and Kosrae, and 6 to 8 feet near Majuro, are expected to taper down slowly to around 3 to 5 feet by early next week, as trade swell and localized wind waves decrease. && .Western Micronesia... An unsettled weather pattern continues across far western and central Micronesia, with strong convergent flow along the near-equatorial trough (NET) just south of Palau, and increasing trade-wind convergence over Chuuk State to the south of Chuuk Lagoon. Himawari visible satellite imagery this afternoon shows scattered to numerous showers over the Republic of Palau with the strongest convection just south of Koror. These showers are expected to continue building overnight through early tomorrow morning, before tapering back down to scattered for the remainder of the weekend. Showers look to become numerous again early next week as the NET interacts with a series of trade-wind troughs. To the northeast, partly cloudy skies and isolated showers are seen over Yap Proper, where CIMMS MIMIC TPW shows relatively drier air with PWATs around 1.8 to 1.9 inches. Yap will remain in this drier pattern for the next day or so before a series of troughs bring increased showers on Sunday through early next week. To the east, scattered to numerous showers are seen to the south of Weno, Chuuk, associated with the far western periphery of the ITCZ. This surface convergence and associated convection looks to lift a bit further north over the next day or so, maintaining scattered showers over the area through at least Saturday, before a relatively quieter period on Sunday. A series of trade-wind troughs will bring on-and-off scattered showers for Chuuk for much of next week. Latest altimetry shows combined seas of around 3 to 5 feet near Palau and 4 to 6 feet near Chuuk. These conditions will continue through the weekend with seas coming down by a foot or so early next week as wind waves and swells diminish. Winds will be moderate to fresh near Yap for tonight, coming down to gentle to moderate through early next week. Trades will be gentle to moderate for Palau, but some stronger gusts can be expected tonight and tomorrow morning with numerous showers in the area. Near Chuuk, winds will be gentle to moderate, becoming moderate to fresh Sunday into early next week. && .GUM WATCHES/WARNINGS/ADVISORIES... GU...None. MP...None. Marianas Waters...None. && $$ Marianas: Bowsher East Micronesia: Montvila West Micronesia: DeCou ####018004132#### FXUS63 KIWX 160752 AFDIWX Area Forecast Discussion National Weather Service Northern Indiana 352 AM EDT Fri May 16 2025 .KEY MESSAGES... - Severe thunderstorms are possible from 6-11pm EDT this evening. The greatest risk will be in the southern half of our area. - Damaging straight-line winds will be the primary threat but hail and tornadoes cannot be ruled out. - Dry weather returns for the weekend with highs in the 60s to low 70s. && .DISCUSSION... Issued at 352 AM EDT Fri May 16 2025 Round 1 of severe wx has ended and we now prepare for a potential round 2 later today. Deep upper low will continue to pinwheel over the Upper Midwest with a second embedded shortwave swinging through our area later today, pulling the upper low further ESE and pushing a surface occluded/cold front through the area. This front passes during the favorable time for severe weather (early evening) but the instability picture is much more muddled today. Cold midlevel temps will support decent midlevel lapse rates but surface dewpoints will only be around 60F at best. This keeps SBCAPE values generally at or below 2000 J/kg. There will be a stout capping inversion for much of the day but that does look to break with the passing front roughly 23-03Z. Wind/shear profiles are obviously highly favorable for organized storms if sustained updrafts manage to develop. With the passing front and at least moderate instability there seems like a decent chance for that to happen. Multicell lines/clusters will likely be the primary mode given linear forcing with damaging straight-line winds the primary hazard given 50+ kts of flow not too far from the surface. There is also a secondary hail and tornado risk though. Hail will be somewhat limited by more modest instability but there is likely enough for some 1"+ hail given cold midlevel temps. And while surface winds are not as backed as one would like to see for a tornado risk, the degree of 0-1km shear can't be ignored. 0-3km line-normal shear vectors should also easily exceed 30 kts and will present a QLCS tornado risk (if other storm- scale criteria are met). Our entire CWA will have some chance of severe weather this evening but the best chances appear in our southern half. Potential failure points include more limited instability and later/weaker forcing which would likely lead to a more isolated threat given the lack of a solid/organized convective line. More organized activity south of our area may also limit the threat this far north. Given highly active short-term and relatively quiet weather over the weekend into early next week, did not make any changes to the NBM initialization. Upper low continues to pinwheel east on Sat with just a low chance of a few sprinkles in our N/NE zones. Sunday will be dry and pleasant with cool temps, mostly sunny skies, and low humidity. Precip chances do return to the area late Mon into Wed as another upper low approaches the region. Still some uncertainty with the track of this low but most guidance keeps us on the cooler/more stable side with decent rain chances but a low severe risk at this time. && .AVIATION /06Z TAFS THROUGH 06Z SATURDAY/... Issued at 1228 AM EDT Fri May 16 2025 Storms have moved east of the SBN and FWA terminals; however, convection was trying to back-build toward both sites. Believe by 06Z, storms should be far enough east that they will not be impacting the terminals so left storms out of TAFs. Winds were dropping off (diminishing) rapidly behind the storms, so diminishing winds are reflected in the TAFs and also supported by the latest (01Z) HRRR run. There is a similar setup Friday with storms once again firing late in the afternoon and evening, so have another round of storms mentioned in the TAFs. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...None. OH...None. MI...None. MARINE...None. && $$ DISCUSSION...AGD AVIATION...Skipper ####018005997#### FXUS64 KTSA 160755 AFDTSA Area Forecast Discussion National Weather Service Tulsa OK 255 AM CDT Fri May 16 2025 ...New SHORT TERM, LONG TERM... .KEY MESSAGES... Issued at 255 AM CDT Thu May 15 2025 - Shower and thunderstorm chances for far eastern/southeast OK into northwest AR through mid afternoon today. - An unsettled weather pattern continues through the weekend and into early next week. Severe thunderstorms are expected at times. && .SHORT TERM... (Today) Issued at 255 AM CDT Fri May 16 2025 An active pattern continues across the region today, with shower and thunderstorm chances increasing this morning and afternoon across portions of eastern Oklahoma and northwest Arkansas. A warm front has begun lifting northward across eastern Oklahoma and western Arkansas early this morning as a surface low develops and moves across southern Kansas through the day today. A subtle mid level disturbance, trailing the main synoptic wave over the Midwest, will also track across the Central Plains and into the Mid Mississippi Valley by late afternoon. As rich low level moisture surges back northward this morning behind the advancing warm front, it will interact with the approaching wave and some thunderstorm development is expected over far eastern Oklahoma and northwest Arkansas by mid morning this morning. Coverage is expected to be minimal with this activity due to slowly eroding mid level capping in place. Still, steep mid level lapse rates and robust shear would support severe convection with any storms that do develop in this zone this morning. Large hail will be the primary concern, though all hazards are in play. These storms will race off to the northeast, likely exiting the forecast area by midday. Attention will then turn to the afternoon as the surface boundary pushes back east and southeast with the passing mid level trough axis. Additional robust thunderstorm development is progged along the boundary by mid afternoon. This will likely be right on the eastern fringes of our forecast area, but a short period of severe thunderstorms will be possible, mainly across western Arkansas before the boundary pushes to the east. Storms should be well east of the forecast area by late afternoon with breezy westerly winds following the boundary. Elsewhere, today will be another warm day, with highs mainly in the mid to upper 80s and gusty winds by afternoon. Bowlan && .LONG TERM... (Tonight through Thursday) Issued at 255 AM CDT Fri May 16 2025 Drier air will push into the area for tonight into Saturday morning, with a lull in any thunderstorm activity through the morning hours on Saturday. This will be short lived however as moisture once again lifts back north in response to Lee cyclogenesis ahead of the main upper level storm system digging into the Desert Southwest. This will begin a period of increasing thunderstorm chances from Saturday afternoon through Monday and possibly into Tuesday. While the specific details are still to be determined and will be highly depended on previous days activity, expect periods of thunderstorms through the weekend as modest southwest flow aloft overspreads a seasonally moist and unstable airmass. Severe thunderstorms will be possible each day, with all hazards in play depending on timing and location of relevant features. As it stands now, thunderstorm chances will increase across eastern Oklahoma Saturday afternoon and evening as the warm front lifts northward. Another round of storms is expected into Sunday afternoon and evening as storms develop off a dryline over western/central Oklahoma. The main storm system begins to move into the Plains on Monday ,providing what is likely the most likely day to see more widespread severe thunderstorms across the region. Storms could linger into Tuesday as the slow moving trough axis slides through the area before departing to the east and pushing a rather strong cold front through the area. Cooler and drier air will filter in behind the frontal boundary with noticeably cooler temperatures progged for the rest of the work week. Lows could even dip into the 40s a couple of nights next week with highs mainly in the 70s. Low shower/storm chances enter the forecast again by the end of the week and into next weekend as northwest flow aloft strengthens over the Plains. Bowlan && .AVIATION... (06Z TAFS) Issued at 1224 AM CDT Fri May 16 2025 Largely quiet with VFR conditions prevailing thru the night. There's a low chance for an isolated shower or storm near KFSM over the next couple of hours, so have inserted prob30 mention there. A period of MVFR cigs in the low lvl moisture return is expected from SE OK into NW AR btwn 12 and 18Z. In addition, the latest CAMs suggest that some elevated storms could develop during this time across far NW AR. The going forecast had this covered with a prob30 mention and have elected to go with tempo mention given good model run-to-run consistency. VFR conditions and clearing skies will prevail aft 18Z. Gusty SW to W winds by mid- morning Friday will gradually become WNW by late in the day and subside. Lacy && .PRELIMINARY POINT TEMPS/POPS... TUL 87 57 83 64 / 0 0 10 40 FSM 89 63 88 68 / 30 0 10 50 MLC 88 61 87 66 / 10 0 30 40 BVO 85 51 81 60 / 0 0 0 50 FYV 85 57 85 63 / 40 0 10 60 BYV 84 57 84 61 / 40 0 10 60 MKO 86 57 84 64 / 10 0 20 40 MIO 83 53 80 61 / 10 0 10 60 F10 87 58 84 64 / 10 0 20 40 HHW 87 64 86 67 / 20 10 40 60 && .TSA WATCHES/WARNINGS/ADVISORIES... OK...None. AR...None. && $$ SHORT TERM...04 LONG TERM....04 AVIATION...30