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Office: CLE

FXUS61 KCLE 251107

Area Forecast Discussion
National Weather Service Cleveland OH
707 AM EDT Fri May 25 2018

High pressure centered along the east coast will provide a warm,
south flow to the area. A weakening low pressure system and cold
front will dissipate as it crosses the Great Lakes over the
weekend. Surface high pressure will expand east across the area
on Monday.


No changes for the early morning update.

Original NEAR TERM Discussion...
Directly under the ridge aloft today while the surface high has
shifted east. The models continue to show a plume of lower level
moisture spreading north up the Appalachians and across the Ohio
Valley. With strong subsidence aloft and no trigger, the end result
will probably be just fair weather cumulus in the southeast counties
from Mount Vernon to Canton and perhaps along the lake breeze
boundary as it develops east of Cleveland this afternoon.
Temperatures always over achieve under the ridge and especially this
time of year with the long days/high sun angle. The high temperature
forecast will be at the high end of guidance or above, mostly
in the mid/upper 80s except where the winds come onshore along
the east lakeshore.

Winds will be light tonight but many areas will keep a light
south breeze and temperatures will be warmer than recent nights
with lows mostly in the 60s.

On Saturday we will be in the squeeze play. The deeper moisture and
corresponding increase in instability will likely fire off showers
and thunderstorms near and over the Appalachians by afternoon. The
approaching trough/weak cold front from the west will produce a
scattering of showers and thunderstorms which should push in from
the west. Eventually we will see the activity fill in across
the forecast area. Will use scattered wording for the most part.
Temps should still be warm, maybe a degree or two cooler due to the
clouds and approaching trough.


Ongoing showers and thunderstorms Saturday night should wane with
the loss of diurnal heating, with most of the activity confined to
the eastern part of the area with the passage of a weak trough. More
diurnally driven convection is possible Sunday, however a lack of
forcing precludes any pops higher than low chance/slight chance
across the southeastern half of the area. A secondary cold front
will slip southeast across the area Sunday night into Monday, a
little faster than previous forecasts. Have opted for some low
chance pops across the area Sunday night, with some of the higher
res guidance more aggressive with development ahead of the front.
Any lingering precip Monday should end fairly quickly, with dry
conditions into Monday night as high pressure builds into the area.
Temperatures will be well above normal, with highs in the upper 80s
to low 90s Sunday and Monday, which is a few degrees higher than
previous forecast and close to the warmer MOS guidance.


The aforementioned cold front will become diffuse and wash out just
south of the area on Tuesday/Tuesday night, with ridging quickly
building east across the region. The ridge will be centered over the
mid Atlantic coast by Wednesday, with return flow/WAA regime across
the area. Attention turns to a potential Gulf system moving
northward toward the Ohio valley on Wednesday/Wednesday night. Model
difference are large with the track/intensity of the system, however
medium confidence that some tropical moisture will surge into the
area by the end of the period. Have opted for chance pops Wednesday
night through Thursday to account for this. Temperatures may be a
touch cooler through mid week, but highs still expected to reach the
low/mid 80s, possibly upper 80s Tuesday, which is several degrees
above normal for this time of year.


.AVIATION /12Z Friday THROUGH Tuesday/...
High pressure at the surface and aloft and VFR conditions will
prevail with nothing other than high clouds and a few fair
weather cumulus. A light south flow will be interrupted by lake
breezes at KERI and the Lake Erie lake shore this afternoon.
There may be some local fog/mist Saturday morning by daybreak
but did not include it in any of the TAF forecasts at this time.

OUTLOOK...NON-VFR possible Saturday afternoon through Sunday.


Quiet conditions continue on the lake today with high pressure
centered west of the Great Lakes off the mid Atlantic coast. Winds
will remain southerly through the weekend, generally 10 kts or less.
A cold front will push south across the lake late Sunday night into
Monday, with winds shifting to northerly by Wednesday night. The
front will wash out south of the region, with high pressure centered
across New England and low pressure moving north out of the Gulf of
Mexico keeping winds out of the east around 10 kts Tuesday through




NEAR TERM...Kosarik
SHORT TERM...Greenawalt
LONG TERM...Greenawalt

Office: ILN FXUS61 KILN 251029 AFDILN Area Forecast Discussion National Weather Service Wilmington OH 629 AM EDT Fri May 25 2018 .SYNOPSIS... High pressure will move off to the east today resulting in southerly winds that will bring increasing heat and humidity. Scattered showers and thunderstorms are forecast over the weekend, particularly in the afternoon and evening. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Today surface high pressure will pull east with southwest flow again establishing itself across the region. 850 mb temperatures will modify towards 16 degrees C with mid-level ridging building overhead. Due to the riding and increasing 850 MB temperatures think highs in the upper 80s seems likely. Global and high res models also indicate weak shower and thunderstorm development across our southeast this afternoon (towards Scioto County) as moisture returns. The NAM has PWATs actually rising to around 1.80" while the GFS has values that seem more reasonable or near 1.50". Am not totally convinced we'll see to much in the way of coverage this afternoon (first day of moisture return), but given the weak disturbance from the gulf working north have kept PoPs in for the southeast. && .SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/... This evening into Saturday morning weak PVA will approach the area from the west which will likely bring some form of weakening showers and thunderstorms into the area Saturday morning. During the afternoon Saturday a summer like pattern will begin to take hold as humidity and atmospheric moisture in general returns to the Ohio Valley. Numerous showers and thunderstorms will likely develop Saturday afternoon during peak heating as forecast soundings quickly destabilize. Shear values are extremely low, so am not expecting much in the way of severe. As mentioned above, it appears to be a day of garden variety showers and thunderstorms. Saturday night, the coverage of showers and thunderstorms will slowly decrease as daytime heating is lost. && .LONG TERM /SUNDAY THROUGH THURSDAY/... Mid level short wave energy will push east across the southern Great Lakes through Saturday night. Between this and the loss of diurnal heating, we should see a decreasing chance of showers and thunderstorms from west to east across our area Saturday night. Some mid level ridging will try to build into the region Sunday into Monday, with our area in between the tropical system to the south and an upper level low over the Rockies. This will allow for temperatures to push into mid to upper 80s for highs on Sunday and then the upper 80s to near 90 for highs on Monday. The models are suggesting the possibility of a weak boundary pushing down into the region on Sunday. This, combined with decent instabilities, will result in the possibility for isolated to scattered afternoon/evening thunderstorms. By Monday, there is little in the way of forcing so think any thunderstorm activity will be fairy limited. Moisture associated with the tropical system to our south will work slowly north through mid week. This could allow for a few showers or thunderstorms to sneak into our southern areas by Tuesday, with a better chance of showers and thunderstorms then pushing north across the rest of our area for Wednesday into Thursday. High temperatures on Tuesday will be in the mid to upper 80s with highs mainly in the mid 80s for Wednesday and Thursday. && .AVIATION /10Z FRIDAY THROUGH TUESDAY/... Surface high pressure will slide east of the TAF sites today with winds veering from the southwest. All sites will remain VFR through today with only some passing high clouds. Saturday morning the next upper level disturbance will approach the area with weakening showers and thunderstorms possible. Saturday afternoon, moisture rich air will move across the Ohio Valley allowing forecast soundings to quickly destabilize. As of now have left the TAF sites dry, but future TAF packages will likely have to start mentioning thunder. OUTLOOK...Afternoon and evening thunderstorms are possible Saturday and Sunday. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...None. KY...None. IN...None. && $$ SYNOPSIS...Haines NEAR TERM...Haines SHORT TERM...Haines LONG TERM...JGL AVIATION...Haines