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 181905 AFDILN Area Forecast Discussion National Weather Service Wilmington OH 305 PM EDT Thu May 18 2017 .SYNOPSIS...
-- Changed Discussion --
With an upper level ridge over the southeastern states, generally warm conditions are expected through the weekend, with occasional chances for showers and storms. A cold front will move into the region Sunday, providing a greater chance for precipitation, before drier and cooler conditions move into the area on Monday.
-- End Changed Discussion --
&& .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
-- Changed Discussion --
Breezy southwest flow across the ILN CWA has led to another day with generally warm temperatures, along with dewpoints in the 60s. Disrupting the T/Td/Sky layout over the region has been occasional convection -- first with a band of storms that moved north of Wilmington this morning, and now with cellular development in the southeastern sections of the forecast area. There are no obviously evident sources of forcing, but SPC mesoanalysis suggests around 1500 J/kg of MLCAPE, sufficient for a few strong updrafts. Surface dewpoints appear to align nicely with the current observations on the preliminary/non-operational GOES-16 CH2 visible satellite data, depicting cumulus with very weak vertical extent in the northwestern sections of the CWA, but more congested cumulus further south. Of interest will be the area in the far southwestern sections of the CWA, which has shown some attempts at convecting over the past hour or so. PoPs have been focused in the southern CWA to account for this feature and the ongoing convection, while PoPs were kept low north of Interstate 71 through the evening. The severe threat remains low but not completely zero, but with marginal shear, so far the storms have not shown enough longevity or organization. With that said, there is enough instability to support one or two strong to possibly severe storms. There has been some focus in previous forecasts on development along a cold front moving in from the north, but 12Z model runs were not impressive in their depiction of what this front will be capable of -- its forcing and orientation are not overly favorable in the ILN CWA. This is also in an area where CAPE and moisture are at a minimum.
-- End Changed Discussion --
&& .SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
-- Changed Discussion --
On Friday morning, a southward-moving cold front will be moving into the ILN CWA, with some level of model disagreement regarding the extent of its progression. This boundary will undercut the overall dome of higher theta-e through the low and mid levels, at least temporarily limiting the chances for precipitation in the northern half of the forecast area. Attention will turn to a weak 700mb shortwave moving into central Kentucky by morning, which should help to take advantage of whatever weak surface-based instability (and perhaps some elevated instability) remains in place early on Friday. Precipitation chances are thus expected to gradually increase from SW to NE over the course of the day, though mainly focusing on the southern two-thirds of the forecast area by afternoon, with the slightly cooler and more stable air to the north. There will certainly be a gradient in temperatures across the ILN CWA, which could help focus the convection, which (at its most in the south) will be in an environment with 1500-2000 J/kg of MLCAPE. With generally weak wind shear -- especially in the low levels) -- the severe threat will again be limited to isolated situations in the stronger storm cores. With the axis of the mid-level ridge ending up positioned over the forecast area by late evening into the overnight, chances for precipitation will again decrease, roughly coincident with the usual diurnal cycle as well.
-- End Changed Discussion --
&& .LONG TERM /SATURDAY THROUGH WEDNESDAY/...
-- Changed Discussion --
Active weather pattern through the long term forecast period. Mid level shortwave and associated surface wave of low pressure to eject northeast into the Great Lakes Saturday. Surface frontal boundary which was stalled across the south will lift north as a warm front Saturday. This will keep a continued threat of showers and thunderstorms with the best chance west. In the warm sector expect Saturdays highs to range from 80 to 85. Surface wave tracks across the Great Lakes with associated cold front pushing east across the region Sunday. Model solutions generally a little quicker with the frontal passage. This will bring an enhanced chance for thunderstorms. Have continued likely pops with a period of categorical during the afternoon. With clouds and precipitation, temperatures will be a little cooler, with Sundays highs ranging from the mid 70s west to 80 east. A lingering chance of a post frontal rain shower Sunday night and then drying out Monday as surface high pressure providing a temporary dry period early next week. Cooler temperatures expected Monday with highs a little below normal, ranging from the upper 60s northwest to the lower 70s southeast. Jet energy to carve out mid/upr level low over the Mid MS Vly next week. ECMWF is deeper and further east, so pcpn onset a little delayed and lingers longer. GFS solution is less amplified and more progressive. Uncertainty increases with model solutions diverging on timing and amplitude of this system. Have chance pops developing Tuesday afternoon and across the region Wednesday. Have lingered chance pops into early Thursday and then diminish pops as the upper low is expected to shift east. Highs Tuesday will be close to normal with and generally 70 to 75, and then cooler Wednesday from the lower 60s nw to upper 60s se. Cool readings expected to continue next Thursday with highs in the mid and upper 60s.
-- End Changed Discussion --
&& .AVIATION /19Z THURSDAY THROUGH TUESDAY/... While prevailing VFR conditions ar expected through the rest of the day and into the overnight, scattered shower and thunderstorm development is expected. These storms will be generally disorganized so direct impacts at the TAF sites are uncertain, but if storms occur some brief MVFR/IFR conditions will be possible. Gusty SW winds will diminish in intensity overnight, and chances for precipitation will also wane after 01Z. Overnight and into tomorrow morning, a gradual wind shift to the north is expected, with an area of MVFR clouds moving south into the TAF sites. These MVFR ceilings will likely lift to VFR by early to mid afternoon. Chances for additional showers and thunderstorms will increase from southwest to northeast after 10Z, but again should remain generally disorganized. OUTLOOK...Thunderstorms are possible at times from Friday through Sunday. MVFR ceilings are possible again on Sunday. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...None. KY...None. IN...None. && $$ SYNOPSIS...Hatzos NEAR TERM...Hatzos SHORT TERM...Hatzos LONG TERM...AR AVIATION...Hatzos

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