906 
FXUS61 KCLE 140139
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
939 PM EDT Mon May 13 2024

.SYNOPSIS...
A cold front will slowly sag across the region tonight through
early Wednesday as low pressure slowly tracks from the 
Mississippi Valley tonight to the Ohio Valley by Wednesday. High
pressure will finally build in by Thursday before low pressure
moves into the northern Great Lakes Friday and drags another 
cold front into the region.

&&

.NEAR TERM /THROUGH TUESDAY NIGHT/...
Will continue a dry forecast for the first half of the
overnight. The main concern for rain will be the batch along the
Ohio River in southern Indiana and northern Kentucky that will
lift north and enter the region late tonight. Low confidence in
the coverage and will keep the iso/sct wording in the forecast.

Most of Previous Discussion...
By tonight, the broad shortwave will start to cross the Mid 
Mississippi Valley with an associated surface low moving through
southern Missouri into southern Illinois. This will be a slow 
process however since this shortwave will continue to be fairly 
closed off and separated from the polar and subtropical branches
of the jet, causing the nearly vertically stacked low to not 
make much eastward progress through the period. The center of 
the system only looks to reach the vicinity of southern Indiana,
southern Ohio, and northern Kentucky by early Wednesday. As 
this shortwave/vertically stacked low migrates slowly eastward 
tonight through Tuesday night, a cold frontal boundary will 
slowly sag through the region from NW to SE. This all points to 
increasing chances for showers and a few pockets of convection 
tonight and Tuesday, with the rain chances only slowly tapering 
off from NW to SE Tuesday night into Wednesday. Despite the 
elevated rain chances through the period, coverage does not 
appear to be overly widespread (more scattered in nature). This 
is due to weak overall forcing with this system being displaced 
from the jet dynamics. However, persistent moisture advection 
and weak isentropic ascent as the center of circulation slowly 
progresses east combined with some mid-level PVA supports high 
chance to likely PoPs, with the greatest coverage coinciding 
with the diurnal maximum Tuesday afternoon. Most of the rain 
will be light, but locally higher amounts will occur with any 
convection. The best opportunity for convection/thunder will be 
Tuesday afternoon when HREF guidance projects a few hundred 
joules of surface based CAPE. 

Lows tonight will range from the upper 50s to low 60s. Highs
Tuesday will stay in the low/mid 70s due to the increased clouds
and precip. Lows Tuesday night will average mid/upper 50s as
cooler air gradually filters in.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
Surface low pressure will be tracking through the Ohio Valley 
Wednesday morning as an upper trough and embedded closed upper low 
trail just behind it. Guidance has been trending gradually slower 
over the last few runs with the departure of this system and the 
area will still be along or just ahead of the upper trough axis 
Wednesday morning. It's looking increasingly likely that showers and 
perhaps some thunder will be around on Wednesday, taking longest to 
exit our eastern/southeastern counties. This has led to POPs for 
Wednesday trending a bit higher with further room to trend up if the 
recent trends prove to be correct. We should dry out later Wednesday 
afternoon through Wednesday night. Thursday looks to be mainly dry 
as an upper-level ridge axis slides through, though a combination of 
some weak instability developing with heating and the next shortwave 
approaching from the southwest late in the day may lead to at least 
isolated to widely scattered shower/thunder chances late in the 
day...especially across far eastern OH and PA, and from the west 
into the I-75 corridor. POPs spread east Thursday night as the 
shortwave slides through, though we'll be fighting nocturnal 
stabilization and the forcing should be modest well ahead of the 
next front, so generally have chance POPs for Thursday night. 

Highs on Wednesday are expected to range from the mid 60s to lower 
70s, warming into the low to mid 70s for Thursday. Nighttime lows 
settle well into the low to mid 50s Wednesday night, trending a bit 
milder (from the mid 50s to near 60 for most) Thursday night. Not 
expecting any severe weather this period. Slow cell motions could 
lead to locally heavy rain on Wednesday, though any flooding 
potential should be quite isolated and may depend on if any heavier 
rain amounts occur in the near term and saturate the ground more.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
A warm and somewhat unsettled long term forecast period is on tap. 
For Friday, a trough and associated cold front will be approaching 
from the west with ridging along the East Coast. Expect sufficient 
moisture return and instability ahead of the front for decent shower 
and storm chances Friday afternoon and evening. Agreement on timing 
of the trough and frontal passage for Friday has improved enough to 
introduce likely (60-70%) POPs. We should dry out Friday night into 
Saturday as the trough and cold front exit east, though there is 
still enough uncertainty regarding how quickly the system exits to 
linger low POPs through Saturday, especially farther east/southeast. 
Saturday night and Sunday should be mainly dry as ridging builds in 
from the southwest. We may need to monitor for a decaying cluster of 
showers/storms to ride overtop the ridge and bring some clouds and 
rain potential, especially on Sunday as a warm front lifts through. 
Confidence in the timing / placement of such a feature this far out 
is quite low. Overall it should be a mainly dry weekend, though with 
some uncertainty revolving around if it does rain a bit at some 
point. Greater shower and storm potential is possible Sunday night 
or Monday as the next shortwave and cold front approach from the 
west/northwest, though confidence in details that far out is low.

Temperatures will be slightly above normal (generally in the 70s) 
Friday and Saturday. While the exact values may depend on the timing 
and coverage of any rain, much of the area has the potential to 
surge into the 80s both Sunday and Monday.

&&

.AVIATION /00Z Tuesday THROUGH Saturday/...
Return flow across the region has allowed for some mid-level
cumulus to enter the airspace and will be the only obstruction
to what will likely be a VFR evening and night. A surface front
will slide southeast and allow for isolated to scattered rain
showers overnight, but confidence in rain getting to a terminal
until closer to daybreak is low. The front will enter during the
day on Tuesday and allow for showers and some storms to develop
especially during the late morning and afternoon hours as the
diurnal cycle progresses. Some non-VFR conditions will be
possible with convection and behind the front as it sags
southeast. Haven't hit the non-VFR with the convection hard at
this point as precise timing is low confidence but do have low
VFR and some higher MVFR in the TAFs for late in the period
behind the front. Winds will start southerly ahead of the front
and then shift to the east then northeast behind the front. A
form of a lake breeze may impact KERI Tuesday afternoon.

Outlook...Non-VFR possible in showers and thunderstorms Tuesday
night through Wednesday and again on Friday through Saturday.

&&

.MARINE...
Generally light (15 knot or less) southerly flow continues through 
Tuesday morning ahead of a cold front. The cold front will sink 
south across the lake Tuesday afternoon, flipping winds around to 
the north-northeast. These north-northeast winds do pick up to 
around 15 knots Tuesday night into Wednesday as weak low pressure 
tracks across the Ohio Valley. This will build some 2 to 4 footers 
west of Cleveland Tuesday night into Wednesday morning. The wind and 
wave forecast remains below small craft criteria for this period, 
though it does get fairly close for a time late Tuesday night or 
Wednesday morning. Will continue to monitor trends in the forecast 
given the notoriously annoying northeast wind direction. Winds 
become generally east-northeast through Thursday and should subside 
enough by Wednesday afternoon to allow waves to diminish more into a 
1 to 3 foot range, if not simply 2 or less Wednesday night and 
Thursday. Winds flip around to the south-southwest Thursday night 
into Friday ahead of a cold front. Winds will vary some through the 
weekend as fronts glance the lake but generally look to remain out 
of a west to south direction with headlines appearing unlikely. 

A few thunderstorms are possible over the lake Tuesday into Tuesday 
evening with a cold front, and may again be possible late Thursday 
night and Friday ahead of a cold front. Additional thunderstorm 
chances are possible Sunday and Monday but with low confidence.

&&

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

&&

$$

SYNOPSIS...Garuckas
NEAR TERM...Garuckas/Sefcovic
SHORT TERM...Sullivan
LONG TERM...Sullivan
AVIATION...Sefcovic
MARINE...Sullivan