Area Forecast Discussion
Issued by NWS Wilmington, OH

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000 FXUS61 KILN 250608 AFDILN Area Forecast Discussion National Weather Service Wilmington OH 208 AM EDT MON JUL 25 2016 .SYNOPSIS... A cold front will begin to approach the area overnight and move through the region on Monday. Hot and humid conditions will be present in advance of this feature with thunderstorms possible at times. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... 25.00Z KILN sounding revealed an moderate/strongly buoyant airmass with MLCAPE approaching 2000 j/kg amidst PWAT values of 1.8"+. However, that`s about it in terms of an environment that will support severe weather. Low/deep layer flows are weak /0-6km bulk shears ~20kts/ with even weaker 0-3km shears. DCAPE rather unimpressive as well below 600 j/kg. Been watching evolution of storm clusters in nern ILL/nwrn IND which is being forced by tail end of wrn Great Lakes shortwave trough and attendant cold front. Storms trying their best to organize amidst very strong instby out there /where widespread ~80F dwpts are observed/ but lack of shear is leading to poor organization. Think recent 3-4 runs of HRRR have been generally grasping what will happen...northern portion of the line near Gary Indiana will surge southeast and weaken as it approaches the CWA around 05Z. Central ILL cluster/segment will likely have more staying power due to feed of better theta-e and approaching MCV to the west...but net propagation will be slowly southeast such that this segment will likely never reach sern IND...and if it does...will have gusted out by then with just a threat for showers/isold storms. Going forecast for overnight looks good...given anomalous dwpt field in place bumped up lows a couple of degrees and slowed rain chances down just a bit in the west/north overnight but overall forecast in good shape. && .SHORT TERM /6 AM THIS MORNING THROUGH TUESDAY NIGHT/... Heat and humidity will continue for Monday. Heat index values will be near 100 again with a better chance for this across southern portions of the region. Continued the heat advisory and excessive heat warning across southern portions of the region for Monday. A cold front will move through on Monday. There has been some variability with how much convection will develop with this feature, however given airmass in place believe that preciptiation chances will be likely across the southern portions of the forecast area by late in the afternoon and early evening hours. A few of these storms may reach severe limits with damaging winds the primary threat. Boundary will hold up across southern portions of the area and therefore linger preciptiation chances across the far south through Tuesday night. With CAA across the northern portions of the forecast area on Tuesday believe cu will develop during the day. Even with the CAA expect high temperatures on Tuesday to be in the middle to upper 80s. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... Stationary frontal boundary looks to be positioned along or just south of the Ohio River Wednesday. Boundary will divide a very moist air mass to the south from a relatively drier air mass to the north. Will continue with chance pops for thunderstorms close to and south of the front on Wednesday. Boundary will lift north as a warm front late Wednesday night into Thursday. This will allow precipitable water values to increase northward, placing the CWA back in a very moist environment for Thursday. Models show a shortwave approaching late Thursday or Thursday night. Timing is still somewhat in question, but there is decent consensus on the track which will bring it across the Ohio Valley. Therefore, begin to increase pops for Thursday afternoon and will continue chance pops into Thursday night for possible influence from shortwave. Additional shortwaves may affect the Ohio Valley Friday through Saturday. Details associated with the shortwaves (such as track/timing/strength) are in question and will need to be resolved with time. But the potential for shortwaves combined with a warm moist air mass means that chance pops for convection will continue through at least Saturday. Eventually, a cold front may move through and this could occur late Saturday into Sunday but confidence is low on the timing of the frontal passage. Temperatures are forecast to favor near average to slightly above average values through the long term. && .AVIATION /06Z MONDAY THROUGH FRIDAY/...
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Cold front lies across Illinois. Thunderstorms that have developed in the very humid airmass along and ahead of the front have remained west of TAF sites. Expect a gradual eastward progression of the convection while storms continue show a diurnal weakening trend. Leftover showers may reach DAY around 09Z. BR is forecast to reduce visibility at LUK ILN and LCK early this morning. All sites may then see thunderstorms develop in the vicinity starting around 16Z as forcing increases near the approaching front, while instability rises toward daytime maxima. The chance for thunderstorms will then persist into evening as the front makes its way toward the Ohio River. Will issue amendments to better indicate timing and effects of thunderstorms closer to their time of occurrence. Look for improving conditions late in the forecast as instability drops off with loss of daytime heating. Winds will generally out of the west with speeds close to 10 knots during the afternoon. OUTLOOK...Thunderstorms possible Thursday.
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OH...Heat Advisory until 8 PM EDT this evening for OHZ073-074- 078>082-088. Excessive Heat Warning until 8 PM EDT this evening for OHZ077. KY...Heat Advisory until 8 PM EDT this evening for KYZ089>100. IN...Heat Advisory until 8 PM EDT this evening for INZ075-080.
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&& $$ SYNOPSIS...Novak NEAR TERM...Binau SHORT TERM...Novak LONG TERM...BPP AVIATION...Coniglio is the U.S. government's official web portal to all federal, state and local government web resources and services.