Preview of NWS' New Version of Forecast
This preview is not operational and should not be used for support decisions.

Area Forecast Discussion (AFD)

Issued by Wilmington, OH (ILN)

                            
000
FXUS61 KILN 170251
AFDILN

AREA FORECAST DISCUSSION
National Weather Service Wilmington OH
1051 PM EDT Mon Sep 16 2019

.SYNOPSIS...
High pressure and a dry airmass will build across the region
through the week with temperatures remaining above normal.

&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
Strong mid level ridge over the mid/upper Mississippi River 
Valley. This has resulted in a northwest flow aloft over the 
the Ohio Valley. Surface cold front which has pushed south of 
ILN/s FA will continue south thru the TN Valley overnight. 
Surface high pressure will build across the Northern Great 
Lakes, causing the low level flow to veer to the northeast. 

Weak low level CAA will occur thru the night with an advection
of low level moisture into the area from the northeast
overnight. Surface dewpoints are still in the lower and middle 
60s. This scenario should lead to the development of stratus. 
Question revolves around how far south the stratus will make it 
by sunrise. Have brought low clouds into about the northern half
of ILN/s FA but confidence in exactly how far south these 
clouds develop is not high. Further south where clouds do not 
make it some valley fog will be possible in the protected 
areas.

Lows tonight are expected to be in the low to mid 60s.

&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
Some possible clouds across the area Tuesday morning should
scatter out into a cu field as high pressure and a drier airmass
builds into the region. Highs on Tuesday will be in the low to
mid 80s with lows Tuesday night in the upper 50s to lower 60s.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
For the start of the long term period, the strong shortwave energy 
currently over the Pacific Northwest will be ejecting northeast into 
Manitoba over the high amplitude ridge, whose axis is forecast to be 
centered over the central Great Lakes.  Meanwhile, a closed low will 
be coming onshore coastal Washington State.  East of the ridge, a 
persistent downstream trof will linger over New England.

The period begins in the local area with surface high pressure in 
place over New England, and dry easterly flow across the CWA. 
This surface high shifts to the south heading late into the work 
week and into the start of the weekend as low level flow swings 
around to the southeast and south. Under the strong mid level ridge, 
high temperatures will likely continue to run 10-12 degrees above 
seasonal normals for mid September.

As the Pacific Northwest closed low opens into a trof and slowly 
ejects eastward, the ridge shifts eastward and begins to flatten on 
Sunday and Monday as the trof slides across the Great Lakes. As 
heights lower, expect a cold front to drop southeast across Ohio 
late Sunday night into Monday, with clouds and precipitation 
persisting through the day Monday. This front will also lower the 
anomalously high maximum temperatures in place since the second week 
of September.

&&

.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
Surface cold front which has pushed south of the Ohio River will 
continue south thru the TN Valley overnight. Surface high
pressure will build across the Northern Great Lakes, causing 
the low level flow to veer to the northeast. 

Scattered to few cu will diminish through the evening hours. 
Low level weak CAA pattern with low level moisture advecting 
down into the area overnight. 

There continues to be uncertainty to the southern push of these 
low level clouds. Trends are a little less pessimistic,
therefore have limited MVFR ceilings to the far north late
tonight into early Tuesday. In the far south, where widespread 
status is not expected to develop have a mention of river 
valley fog with vsbys dropping to IFR at KLUK valley location. 
 
The low clouds will lift into a scattered cu field Tuesday
morning with a return to VFR conditions. 

OUTLOOK...No significant weather expected.

&&

.ILN WATCHES/WARNINGS/ADVISORIES...
OH...None.
KY...None.
IN...None.

&&

$$
SYNOPSIS...JGL
NEAR TERM...AR
SHORT TERM...JGL
LONG TERM...Hogue
AVIATION...AR