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FXUS61 KCLE 222358

Area Forecast Discussion
National Weather Service Cleveland OH
758 PM EDT Thu Jun 22 2017

A warm front will lift across Lake Erie this evening.
Low pressure over the western lakes will move northeast into 
Canada by Friday, bringing a cold front east across the region. 
A broad trough of low pressure will then remain over the area 
through the weekend. High pressure at the surface will begin to 
move in from the west Monday night into Tuesday.


Broken line of convection that developed across NW OH has moved
North of the forecast area. Think for the rest of the evening
will be hit or miss with the heavier rain moving into the area
after midnight. So will continue with chance pops this evening.

Original discussion...
Warm front located from southern Michigan to NW PA. This
boundary should continue to lift northward through the evening
and be north of Lake Erie around midnight. The better shear and
instability was located across NW PA. If any storms get stronger
it will be across this area through early evening. Cant rule 
out an isolated thunderstorm elsewhere in the warm sector. 
Confidence in any thunderstorm development is low. 

We will then watch the moisture advection increase ahead of low
pressure that will move into the central Great Lakes. There will
be tropical moisture into the area but the main focus appears to
be south of the county warning area until the cold front arrive
Friday afternoon into the evening. Locally heavy rainfall will
be possible but mainly across the eastern half of the area.
Drier air moves back into the region Friday night with
showers/thunderstorms ending from west to east. 

Warm tonight with the increased moisture. Lows will likely be
within a couple degrees of 70 at most locations. Humid on friday
but with rain and cloud cover highs will be in the mid 70s to
lower 80s. Cooler Friday night in the wake of the cold front.
Lows should dip back into the 50s away from the lake.


A surface cold front will move east with waves of low pressure 
expected along the frontal boundary Friday night allowing ridge of 
high pressure to build into the local area for Saturday. The ridging 
will be dominant through the day Sunday and surface trough of low 
pressure will begin to push south across the area Sunday.

Some weak cold air advection will take place Saturday and Sunday 
with highs remaining on the mild side in the lower 70s.  Lows during 
the night will hover in the middle 50s.


Broad upper level troughiness will prevail through Tuesday night 
over the eastern United States.  Nearly zonal flow will setup by mid 
week with a small shortwave trough advancing east into the eastern 
portions of the United States by Wednesday and Thursday.  Due to the 
fast moving systems and long period of cyclonic flow expected across 
the area aloft, the atmosphere will be in a chaotic state of change 
through the forecast period.

Another wave of low pressure will move east across the forecast area 
Monday into Tuesday and then shift east of the area Tuesday night. 
Through this process, weak cold air advection will take place into 
Tuesday.  High pressure with a ridge extending north to the Great 
Lakes will advance east Tuesday night into Wednesday allowing a 
return back to warm air advection.  Yet another low pressure system 
will move quickly east across the central Great Lakes Thursday night 
into Friday morning.

Limited instability is expected across the area through the period 
with cold air advancing in during the early periods and this should 
limit thunder threat.  Then, as warm air advection moves in, 
destabilization will take place across the area and increase threat 
for thunderstorms. 

Cold air advection early in the period will keep temperatures quite 
cool. Highs by Thursday may wind up being under forecast due to the 
potential for stronger warm air advection and if sun has a chance to 
break through the cloud cover and the showers and thunderstorms.


.AVIATION /00Z Friday THROUGH Tuesday/...
Deeper moisture continues to stream north into the area. There
will be a chance of showers pretty much anytime but will
emphasize showers for the second half of the night as the 
upward motion will increase ahead of a cold front from the
western Great lakes. MVFR ceilings and areas of IFR ceilings 
will develop as the lower layers become saturated later tonight 
and early Friday morning. The rain may remain showery but given 
the frequency of the showers expected, made the showers 
prevailing in the forecast by Friday morning. Thunder is 
possible almost at any time as well but given the uncertainty of
timing, put thunder vicinity for much of the time. The 
showers/storms will taper off from northwest to southeast later 
Friday afternoon and evening as the cold front pushes across 
the area. 

OUTLOOK...Chance of brief MVFR in showers Sunday into Monday 
with a cold front and trough aloft.


Southwest flow will persist through Friday in the warm air 
advection.  A shift to a west northwest direction will take place 
Friday afternoon as a cold front moves east of the area.  Flow 
should be light enough to support 2 to 4 foot waves and avoid small 
craft advisories.  Increasing winds will take place out of the west 
by Saturday evening.  May need small craft advisories in the western 
half of the lake Saturday evening and over the entire lake by Sunday 
morning in westerly flow. This flow will continue into Monday and 
then fluctuate in speed through Tuesday.





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