425 
fxus61 krlx 061012 
afdrlx 


Area forecast discussion 
National Weather Service Charleston WV 
607 am EDT sun Jul 6 2008 


Synopsis... 
weak wind flow remains through Sunday night. Upper trough drifts 
east into West Virginia...then pulls east Monday afternoon. Cold 
front approaching from the northwest late Wednesday. 


&& 


Near term /through tonight/... 
hard to pinpoint most favored areas for slow moving convection 
today...in this "dog days of summer" weak wind flow. 


Precipitable water is higher along the eastern slopes and point 
east...and what wind flow there is in the low levels - only 5 to 10 
knots to 850 mbs - is from the east/southeast into the mountains. Yet...the 
coolest temperatures aloft under the upper air trough are further 
west...toward the tri state area around heights. Cape of around 2000 j/kg 
develop there this afternoon. 


Ended up increasing probability of precipitation slightly over the mountains...with some 
likely probability of precipitation east of ekn. Probability of precipitation increase sooner over mountains this 
morning than further west. Also Drew the chance probability of precipitation further west under 
the 500 mb trough to include The Heights vicinity for the afternoon. Was 
tempted to remove probability of precipitation toward Perry County Ohio...but held onto a 
slight chance. 


Fog should develop again tonight...but figuring on a hour to two 
later. Kept temperatures along river valleys at or above most 
minimum temperature guidance. Cooled down some rural 
areas...including interior southeast Ohio. 


&& 


Short term /Monday through Wednesday/... 
hard to rule out precipitation anywhere on Monday...as upper 
trough/weak closed low continue to drift eastward. Moisture depth 
becomes an issue...especially along/west of the Ohio River. 
Instability appears sufficient for a few showers/storms to stand 
up. Weak wind flow will keep pulse activity from moving anywhere 
fast. County Warning Area will be in a relative minimum of precipitable water values under 1.5 
inches...so rainfall should not be too intense. Still think 
activity will be fairly sparse. Kept chance probability of precipitation confined to the 
higher elevations...with slight chance to the west...and sub-15 probability of precipitation 
in southeast Ohio. Activity dies down Monday evening with loss of 
heating. 


H500 heights begin to recover slightly on Tuesday as trough pulls 
away. Center of Bermuda high may actually drift west 
slightly...allowing low level flow to turn southwest. Thus... 
moisture starts to creep back into the area. Certainly not a rapid 
increase with h850 winds struggling to reach 20 knots...but we 
should see better coverage Tuesday afternoon...with even some modest 
midlevel q-vec convergence and isentropic lift in the west. 


Activity once again dies down somewhat Tuesday evening...but should 
be supported into the night by slow approach of frontal boundary 
from the northwest. Timing issues remain...with the GFS appearing 
to be a touch quicker to bring the front south than the 
NAM/sref/ECMWF. Previous grid ideas looked decent...leaning towards 
the compromise solution...and only made minor changes. Brought 50 
probability of precipitation to southeast Ohio prior to 12z Wednesday and 50 probability of precipitation areawide 
during the day. Likely values will probably be needed soon. 


Temperatures did not stray too far from guidance...although I tended 
to lean towards warmer values in the western counties both Monday 
and Tuesday...given slightly less cloud cover/rain coverage here. 
In any case...do not foresee widespread 90-plus values either day. 


&& 


Long term /Wednesday night through Saturday/... 
operational European model (ecmwf) and GFS show some fairly sizable differences for 
the extended forecast. Will stay close to the European model (ecmwf) ensembles for 
the forecast period. This brings a cold front over the region on 
Wednesday...stalling around or south of the region on 
Thursday...then moving back north as a warm front for Saturday. 


&& 


Aviation /10z Sunday through Thursday/... 
conditions improving 12z to 14z with widespread fog and stratus 
evaporating. Scattered to broken cumulus at 2 to 4 thousand feet above ground level and visibility 5 to 6 
miles in haze by 14z. Isolated to scattered slow moving 
convection possible after 15z. Hard to Pin Point most favorable 
areas for convection in this sluggish wind pattern...but moisture a 
bit deeper over the mountainous counties. 


Visibility lowering again after 03z Monday with fog developing in river 
valleys top widespread visibility below 3 miles and areas of stratus below 
1 thousand feet broken. 


Aviation outlook /after 12z Mon/...IFR conditions in fog in 
river valleys at 12z Monday should evaporate quickly. 


&& 


Rlx watches/warnings/advisories... 
WV...none. 
Ohio...none. 
Kentucky...none. 
Virginia...none. 


&& 


$$ 


Synopsis...ktb 
near term...ktb 
short term...cl 
long term...rpy 
aviation...ktb