469 
FXUS61 KCLE 112228
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
628 PM EDT Wed Sep 11 2019

.SYNOPSIS...
A cold front located from central lower Michigan and southwest 
Ontario will settle south tonight into Lake Erie and sag further 
south into central Ohio on Thursday. The front will drift north 
Thursday night. A cold front will follow from the west Friday 
afternoon and evening.

&&

.NEAR TERM /THROUGH THURSDAY NIGHT/...
Showers and thunderstorms are expected to continue through the
night. Most of the activity is developing on outflow boundaries.
Expecting a possible uptick in activity across the north as the
cold front creeps south toward the region. Made some minor 
adjustments to hourly temperatures and dewpoints this evening. 
Otherwise, no major changes to forecast at this time. 

Previous Discussion...

Scattered showers and thunderstorms continue to develop and have 
slowly increased in intensity this afternoon but have remain below 
severe limits for the most part. Wind shear is highest further north 
near Lake Erie with effective shear of 30-35 knots. LCL heights are 
above 1000 m which will decrease the threat of tornadoes. PW values 
are near 1.7" which has kept DCAPE generally below 700 J/KG. MLCAPE 
has been around 1500 to near 2000 J/kg. There is just enough wind 
shear over the northern counties of Ohio to sustain some 
organization of the storms so the threat of damaging wind and 
isolated 1" size hail will continue for the next several hours.

There will be diurnal stabilization of the boundary this evening so 
convection should decrease but there is still a question of whether 
or not more convection further north from Michigan will spread 
southeast across the area after midnight. The cold front to the 
north will move into Lake Erie late tonight and sag into the 
southern Lake Erie lake shore Thursday morning and into central Ohio 
during the afternoon. POPs will diminish during the morning and then 
increase in the afternoon over the southwest part of the CWA. 

The front will lift north Thursday night as a diffuse warm front 
especially over the western part of the CWA.

With the frontal boundary in the area, temperatures will vary widely 
from the north to the southern counties on Thursday.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
Low pressure will pass north of Lake Superior on Friday, lifting
a warm front back north across the area. We will only be in the
warm sector for a relatively short window as the associated 
cold front sweeps in from the west late Friday afternoon into 
Friday night. Tried to refine pops on Friday, with the highest
values in NW Ohio during the afternoon, expanding east across
the area during the evening and overnight hours. Given the front
reaching northwest Ohio at peak heating, will need to monitor
for a few stronger storms Friday afternoon, mainly west of I-71.
Also raised highs a few degrees Friday, especially along the
northeast lakeshore where temperatures may over achieve with
southerly downsloping flow. 

High pressure and drier conditions return on Saturday.
Temperatures will drop back to near or just slightly above
normal.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
Models show an amplifying upper level ridge building back over
the area for the first half of next week with above normal 
temperatures appear likely through the long term. The GFS tries
to bring a wave of low pressure across the central Great Lakes
with a cold front pushing south into the area Monday night
followed by cooler temperatures by Tuesday and Wednesday. Given
the strength of the upper ridge overhead, will lean towards the
other long range models with heat continuing into the middle of
the week.

&&

.AVIATION /18Z Wednesday THROUGH Monday/...
Generally VFR conditions will continue into much of the
afternoon as showers and thunderstorms develop and increase in
coverage and intensity through 21 UTC. Cumulus field will
increase and become broken as well. MVFR conditions will develop
in the heavier downpours. Brief improvement can be expect early
this evening but lower clouds and some fog may develop after
midnight as the cold front to the north approaches from the
north along with lingering moisture in the boundary layer.  The
boundary will sag south into northern Ohio and nw PA Thursday 
morning and bring IFR to MVFR cigs.


.OUTLOOK...Non-VFR conditions possible in showers/thunderstorms
Thursday through Saturday morning and again in showers next week
Monday and Tuesday.

&&

.MARINE...
A frontal boundary located just north of Lake Erie will push
south across the lake on Thursday with northeast winds
increasing to 15 to 25 knots from east to west during the
afternoon and evening. Small Craft Advisories accomapnied by a
high swimming risk will likely be needed for most of the lake 
east of the Islands Thursday afternoon and evening. Water levels
will also rise on western basin of Lake Erie with the east to
northeast flow Thursday night but at this time are expected to
peak at or below flooding levels.  

This boundary will lift back north as a warm front on Friday
with a cold front sweeping east across Lake Erie on Friday
night. High pressure will expand from west to east behind the
front on Saturday and linger into the early part of next week.

&&

.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...None.
MARINE...None.

&&

$$
SYNOPSIS...LaPlante
NEAR TERM...LaPlante/Lombardy
SHORT TERM...KEC
LONG TERM...KEC
AVIATION...LaPlante
MARINE...KEC