Area Forecast Discussion
Issued by NWS Wilmington, OH

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000 FXUS61 KILN 151428 AFDILN Area Forecast Discussion National Weather Service Wilmington OH 928 AM EST Thu Feb 15 2018 .SYNOPSIS... An upper level disturbance interacting with a cold front will produce widespread showers today. Some locally heavy rain will be possible this afternoon into Friday morning. Drier air and colder temperatures are expected Friday with high pressure arriving behind the cold front. Showers then look to return to the region Monday. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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Warm front has lifted across the area allowing temperatures to warm to at least 50 degrees. Being in the warm sector, we are seeing a relative break in the precipitation as weak PVA moves across the southeastern zones allowing for some light returns, but with dry air remaining around 700 MB have limited PoPs. The main batch of QPF will arrive early this afternoon as the upper level jet quickly strengthens and PV ripples along a baroclinic zone just north of our area, producing frontogenesis. As the slow moving, parallel to the mid level flow boundary moves closer, initial precipitation looks to concentrate across north/central Ohio and then will likely fill in further south toward evening. PWATs ahead of this approaching front are around 1.3" to 1.4" (in record territory for this time of year) and with warm cloud depth layers forecast to be between 9 and 10 kft heavy rain will be possible. Temps that are rising into the 60s to near 70 will allow surface based CAPE of 200 J/KG to develop, warranting a chance of thunderstorms this afternoon and evening.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/... Late Thursday night into Friday morning the upper level jet continues to strengthen with widespread divergence and weak diffluence occurring. The upper level energy will finally begin to head east late Thursday night allowing the front to start to push southeast. As this happens widespread showers will likely begin to consolidate into a linear fashion. It should be noted that the NAM and GFS have some (very little... but not zero) MUCAPE this afternoon and along the surface low. Given this isolated thunder can`t be ruled out, but have left out of the forecast for now. Late Thursday into early Friday morning a second wave of stronger PVA will move across the baroclinic zone offering another possible round of heavy rain. PWATs and warm cloud depth layers remain favorable and this second round is what helps to push global QPF fields in the 1 to 2" range. Overall the NAM, GFS, ECMWF, and CMC have the highest QPF footprint towards Pittsburgh, but still show a swath of 1 to 2" across our northern zones (stretching from around PIT to CMH to DAY). Looking at the latest GEFS and EPS exceedance plots also supports the above. WPC has kept the area in a slight risk for excessive rainfall on Day 1. Given the above have issued a flood watch for the eastern half of the forecast area. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... The 00Z models continue to vary with how far north to bring the precipitation associated with some southern stream energy moving across the Tennessee Valley over the weekend. There is also some discrepancies in how much interaction there will be with some weaker northern stream energy moving across the Great Lakes region. The overall trend looks to be a more southern track with the southern system so will trim back pops initially across our south and overall in general. However, with the possibility of some phasing with the northern system, will hang on to at least some chance pops across the entire area Saturday afternoon into Saturday night. With the slower pcpn onset on Saturday, it looks like we should be warm enough for any pcpn to start off as primarily rain. As we start to get on the back side of the system and some cooler air begins to work in, will then hang on to a transition to a rain snow mix across mainly our north heading into Saturday evening with the pcpn then tapering off fairly quickly overnight Saturday. High pressure will build quickly east across the area through the day on Sunday. This will provide for dry conditions with highs mostly in the 40s. Moist southwesterly flow will then develop across the region through mid week ahead of a slow moving cold front sagging down across the Midwest. Several waves of low pressure are forecast to ride up along the front and this will likely result in several rounds of rain showers across our area through the remainder of the long term period. Some marginal instabilities will begin to work their way northward into our area so we may eventually need some thunder wording, but with it being so far out and some timing differences between the models, have left pcpn as just rain showers for now. Given the possibility for an extended period of pcpn, will continue to mention a flood potential in the HWO product. In a good WAA pattern, temperatures will be well above normal Monday and Tuesday and possibly into Wednesday, depending on the eventual timing of the cold front through our area. && .AVIATION /14Z THURSDAY THROUGH MONDAY/... Weak warm air advection is currently pushing across the area with moderate drizzle through northern Kentucky. The forecast area is also mostly VFR this morning, but MVFR and IFR reside just to our south and west. Most of this morning will likely be precipitation free (besides light drizzle) ahead of the next shortwave. Early this afternoon the shortwave will approach the TAF sites with widespread showers moving in from the west. The showers will likely start at KDAY first and then progress east towards KILN/ KCMH/ and KLCK. Showers will then fill in from the west. Precipitation will continue through the afternoon into early evening with ceilings coming up a bit in any heavier precipitation (due to mixing). Visibilities will likely be IFR though. Late Thursday evening a surface low will move across the area with a cold front slowly marching southeast. Latest run of HRRR and NSSL WRF now show a line forming along the front. The HRRR in fact shows CAPE meaning thunder will be possible. For now will hold off until more model run consistency exists. OUTLOOK...MVFR to IFR conditions are expected to continue through Friday and return on Monday. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...Flood Watch from 4 PM EST this afternoon through Friday afternoon for OHZ043>046-051>056-061>065-071>074-079>082- 088. KY...Flood Watch from 4 PM EST this afternoon through Friday afternoon for KYZ100. IN...None. && $$ SYNOPSIS...Haines NEAR TERM...Coniglio/Haines SHORT TERM...Haines LONG TERM...JGL AVIATION...Haines

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