625 
fxus61 krlx 040232 
afdrlx 


Area forecast discussion 
National Weather Service Charleston WV 
1032 PM EDT Thursday Jul 3 2008 


Synopsis... 
a front stalls over the middle Ohio Valley tonight...bringing wet 
weather through Sunday. Front moves off to the east Monday...but 
another front arrives the middle of next week. 


&& 


Near term /through Friday/...updated... 
latest radar trends indicate vorticity maximum currently over Ohio River 
near pkb and moving east. Associated rain showers will gradually weaken as 
they move across the north...with loss of daytime heating. NAM and 
RUC seem to have a good handle on aforementioned vorticity maximum. Lowered 
probability of precipitation to high chance across the north as vorticity shifts eastward over the 
next few hours. Another area of vorticity interacting with frontal 
boundary over northern Kentucky sparking convection. This is prognosticated to 
slowly move east toward eastern Kentucky after midnight. With boundary 
slowing to a position near Ohio River and waves riding along 
it...dont feel confident in lowering probability of precipitation below chance through the 
night for areas west of i79...despite models showing little to no 
quantitative precipitation forecast overnight. 


..previous discussion below... 
Cold front across southeast Ohio this evening along with showers 
and thunderstorms. Minor tweaks made to probability of precipitation and weather from 
previous forecast keeping categorical probability of precipitation across the northwest 
sections...and chance probability of precipitation across the rest of the area except our 
Virginia counties. A short wave is evident in WV satellite and radar 
images over southern Ohio...northern Kentucky border moving east. This 
wave will move over WV this afternoon and evening...and together 
with plenty of sunshine observed this afternoon...it will bringing 
extra forcing for thunderstorm activity. 


Radar and satellite images suggest showers activity along the front 
is moving slowly east...minimizing water problems this afternoon and 
evening. However...the front should become stationary overnight... 
while couple of waves move along the boundary tonight and Friday. 


For temperatures...plenty of clouds overnight mainly across the 
western two thirds and southwest flow should keep warm temperatures 
overnight. Went closer to the warmer met...but cooler closer to the 
mav over the eastern mountains where less clouds are expected. 


For highs on Saturday...went with the cooler mav as plenty of 
clouds...showers become a factor. 


&& 


Short term /Friday night through Sunday night/... 
models show a wave moving across the region Friday night with 
frontal moisture pushing a bit further south...but remaining over 
much of the region. Models have some minor timing differences on 
wave moving through and position of moisture behind the front. Since 
differences are fairly minor...will run a compromise between models 
for now. Chances of showers and thunderstorms remain over the region 
where moisture lingers on Saturday and Sunday...with best chances in 
the afternoon and early evening hours. 


&& 


Long term /Monday through Thursday/... 
went with a European model (ecmwf) ensemble blend for this period. This shows a 
frontal boundary sliding into the region for middle week and then 
stalling over the area. 


&& 


Aviation /03z Friday through Tuesday/... 
area of rain showers associated with vorticity maximum will move east of area and 
weaken by 04z. VFR will prevail for the most part outside of rain showers. 
Brief MVFR visible in rain showers for pkb 00-01z...ckb and ekn 00-03z. 


MVFR fog/stratus will form across north overnight...with a few breaks in 
the clouds. Exception being pkb and ekn where IFR ceiling/visible 
08-12z. 


A cold front will slowly move southeast to affect the central and 
eastern sections of WV by Friday afternoon. Models indicate another 
vorticity maximum will move along front Friday morning to affect 
heights...pkb...and crw with rain showers. Inserted MVFR visible for these areas 
13-16z. Rain showers and a few -tsra will expand across the area into the 
afternoon for most areas. Expect mostly MVFR visible in the afternoon 
rain showers. 


Aviation outlook /after 00z Sat/...IFR conditions possible in 
thunderstorms Friday night into Saturday morning. 


&& 


Hydrology... 
the threat of high water we have been highlighting the past few days 
still could become a reality. 18z/21z especially illustrate a baroclinic 
zone stretched out over WV into central Kentucky this Holiday weekend. Middle level 
winds will be parallel to the front indicating possible training of 
storms. Rolled with a HPC/sref quantitative precipitation forecast blend which hits northern WV the 
hardest with 2.0 inches plus from Friday - sun. Lowest amounts are northwest 
/Perry/ and southeast /swrn Virginia/ where 1.5 is forecast. These numbers reside 
between the mean and higher end of the sref members and less than 12hr 
ffg. With the forecast driven by mesoscale features flash flood advisory would be 
premature at this point. Best course of action is too see where and 
how much quantitative precipitation forecast falls today then go from there. The ground should hold the 
rainfall today. Its the placement/track of Friday ngts wave that bears 
watching. 


&& 


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


&& 


$$ 
Synopsis...arj/rpy 
near term...arj/30 
short term...rpy 
long term...rpy 
aviation...30 
hydrology...