Area Forecast Discussion
Issued by NWS Wilmington, OH

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KILN 141103 AFDILN Area Forecast Discussion National Weather Service Wilmington OH 603 AM EST Wed Feb 14 2018 .SYNOPSIS... A warm front will lift north today bringing cloudy skies, much warmer temperatures, and light rain to the region. An upper level disturbance will then move across the area Thursday into Friday bringing more rain. A cold front will then cross the Ohio Valley Friday morning bringing temperatures back to normal. && .NEAR TERM /UNTIL 2 PM THIS AFTERNOON/... Cloud cover will remain through the near term as we move into an active period. This morning the much anticipated upper level low can be seen rotating off the coast of California on water vapor. This upper level low working in tandem with a strengthening mid-level ridge over the Gulf of Mexico will allow for multiple rounds of precipitation through the end of the work week. As the low detaches from the main flow today the sub-tropical jet will modulate and head northeast. A LFQ will then rotate over the area with a warm front washing north. The forecast remains extremely complex today though given to a number of conflicting processes. The day will open up with the LFQ approaching and forecast soundings saturating (PWATs over 1.00"). Across our far northern zones though GFS and NAM forecast soundings show dry air in the 700 to 500 MB layer that never really goes away. This appears to be due to the northern extent of the sub-tropical jet and warm front. So this morning have delayed the onset of precipitation while also keeping the north dry. This afternoon the jet will stop heading north around KDAY and KCMH. This means the warm front will stall around the same area. North of the front forecast soundings don`t completely saturate and drizzle will be the predominant weather type. Along the front showers will be likely. South of the front there will be a break in the showers until the evening (in part thanks to the LRQ or upper level convergence). && .SHORT TERM /2 PM THIS AFTERNOON THROUGH THURSDAY NIGHT/... This evening a weak shortwave will be approach from the west with a weak WAA footprint seen on the 850-700 MB layer. This can also be seen weakly on the omega fields not surprisingly (even though it is weak thanks to almost neutral vorticity advection). Thursday morning on the back side of the wave drier 700 to 500 MB air moves into the area likely confining any precipitation to being very light or drizzle. Thursday around day break the upper level low over California will shear out and be absorbed into a secondary piece of energy diving southeast out of British Columbia. As this happens the upper level jet will rapidly strengthen with a frontal zone approaching from the northwest. The mid-level ridge is a little bit stronger than it was before, but showers look to return Thursday thanks to the abundant moisture and potent lift. PWATs on the GFS are forecast to be around 1.45" with the NAM showing values around 1.35". Both of these values are in record territory for this time of year. Warm cloud depth layers on the GFS are forecast to be around ~9kft while the NAM is showing values around ~10kft. Right at the end of the near term the surface low will be approaching from the west giving the best chance for heavy rain. && .LONG TERM /FRIDAY THROUGH TUESDAY/... A surface low will push east across the southern Great Lakes Thursday evening with a trailing cold front moving southeast across our area later Thursday night into Friday morning. Widespread rain showers should be ongoing across the area early Thursday evening, especially across northern portions of our fa, closer to the front. This area of pcpn will then sag southeast with the front through Thursday night. Ahead of the front, PWs will be near or slightly above 1 inch Thursday night and with good forcing along the front, moderate rainfall will be possible for a fairly extended period of time. Storm total QPF values of 1 to 1.5 inches will be possible through Thursday night. This will likely lead to rises on creeks and streams as well as some possible flooding. With th bulk of the heavier rain still being mainly in the fourth period and still some uncertainty as to exactly where the heaviest axis will setup, have opted to hold off on a flood watch at the moment and continue with a mention in the HWO product. Drier air will work in from the northwest behind the front through the day on Friday. This will allow for pcpn to taper off northwest to southeast during the day. As cooler air begins to filter in, there could be a brief period of mixed rain/snow or snow on the back end. Forecast soundings for the most part though do not cool off enough for this until the pcpn pretty much comes to an end. In the developing CAA pattern, temperatures will fall into the 30s through the day on Friday. There is still some uncertainty with the northern extent of the next surface low moving across the Tennessee Valley Saturday into Saturday night. The 00Z GFS and CMC are quite a bit farther north than the 00Z ECMWF, which only brings pcpn into our far southern areas. Will take a bit of a blend and allow for chance pops to spread into most of the area but only go likely along and south of the Ohio River. Depending on how fast the pcpn moves in, in may start off as snow or a rain/snow mix before transitioning over to mainly rain through Saturday afternoon, before possibly transitioning back to a rain/snow mix Saturday night before ending. Expect highs on Saturday mainly in the mid to upper 30s, modifying to highs in the low to mid 40s by Sunday. The upper level trough over the west coast will begin to transition eastward through the first part of next week. This will allow for a slow moving cold front to work slowly southeast across the Midwest. Moist southwesterly flow ahead of this will likely lead to an extended period of pcpn chances through the remainder of the long term period. There is some uncertainty though as to just how fast the front will work its way eastward toward our region so will still just keep pops in the chance to likely category for Monday into Tuesday. In the southwest flow pattern, temperatures will remain well above normal through the first part of the week. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
-- Changed Discussion --
Surface warm front is slowly lifting north this morning and approaching the area from the south. Have gone ahead and delayed the onset of MVFR a little bit from previous TAF issuance, but the MVFR and IFR deck is waiting just to our south in Kentucky. During the afternoon today light rain will be move into our southern TAF sites with the primary show being along a stalled warm front. High res models have shown some consistency with this and depicts the warm front as a band of showers from west to east this afternoon. Latest runs have in general shown the KDAY to KCMH line as being the primary area of interest. This could easily change though and only light rain is expected outside of this zone. Overnight tonight into Thursday morning widespread IFR or lowers cigs and vsbys will be possible just north of the warm front. As of now this appears that it will setup just north of the TAF sites. This will have to be closely monitored though, and even still IFR conditions are expected overnight with only slight to no improvement. OUTLOOK...MVFR to IFR conditions are expected Thursday into Friday.
-- End Changed Discussion --
&& .ILN WATCHES/WARNINGS/ADVISORIES... OH...None. KY...None. IN...None. && $$ SYNOPSIS...Haines NEAR TERM...Haines SHORT TERM...Haines LONG TERM...JGL AVIATION...Haines

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.