234 
fxus61 kbgm 232338 
afdbgm 


Area forecast discussion 
National Weather Service Binghamton New York 
738 PM EDT Wednesday Jul 23 2008 


Synopsis... 
a slow moving low pressure system will move north of the area tonight 
and drag a slow moving cold front through the region. Showers and 
thunderstorms...some with heavy rainfall will continue this evening 
before pulling east of the area overnight. Somewhat drier weather 
is expected for Thursday along with seasonal temperatures. 


&& 


Near term /until 6 am Thursday morning/... 
as of 530pm...update to remove the watch over my western counties 
where any instability that we had is starting to wane. Further 
south and east...some impressive convection continues over 
southeast Pennsylvania. Will monitor it as it approaches my 
southern zones...but at this time do not see needing the watch 
extended after 00z. Updated zone forecast product to indicate a break in the 
rainfall early this evening over my central counties...but with 
the flow aloft continuing to back aloft and convection continuing 
to develop over the southeastern US...would not be surprised if 
southeastern zones get hit again with more rainfall late tonight. 
New NAM indicates this...but continues to be further west than the 
GFS. This is troubling given the widespread flooding now occurring 
over the Catskills and Poconos. Will see if the 18z GFS continues 
to remain east...which would mostly spare US. 


Updated products are out. 




Previous discussion... 
busy evening at the office with multiple threats occurring at this time. 
Plume of rainfall over my eastern zones is making slow eastward 
progress...but along its eastern flank...convection has blossomed 
with very impressive low level shear. At the same 
time...impressive shortwave over the eastern lakes is spawning 
convection over western New York that is moving east towards my 
western zones. 


Given the setup...felt that Severe Thunderstorm Watch was warranted across 
the entire County Warning Area. In addition...expanded Flood Watch west given 
afternoon rainfall/flooding reports...with warm rain processes 
allowing for high rainfall efficiency in warm moist airmass over 
the southeastern zones. 


Precipitation should pull east of my eastern zones late 
tonight...while convection west of the County Warning Area should die off...so 
have diminishing probability of precipitation as the night GOES on. 


&& 


Short term /6 am Thursday morning through Saturday/... 
with main tropical plume east of the area on Thursday...main 
driver of any rain showers/thunderstorms and rain will be cooling temperatures aloft as the cutoff 
over the eastern Great Lakes makes its closest approach. 
Instability is pretty limited...but convective available potential energy of a few hundred j/kg 
may allow for a few embedded thunderstorms and rain. In any case...a much quieter 
day than today is anticipated. With temperatures aloft pretty cool for 
this time of year /around +12c/ expect highs in the middle 70s under 
limited sunshine. 


Friday...the cutoff lifts out of the region and with temperatures warming 
aloft expect less in the way of rain showers/thunderstorms and rain activity than the day 
previous. With t850 warming to +14c...should see highs reaching 
the lower 80s under increased sunshine. 


On Saturday...next front approaches as northeastern US trough 
reloads. Expect increasing rain showers/thunderstorms and rain chances as the front arrives. 
Convective available potential energy back above 1000j/kg along with good middle level winds 
/30-40kts/ suggests that this will be our next severe weather 
threat. 


&& 


Long term /Saturday night through Wednesday/... 
given all kinds of weather in the short term...have followed HPC 
closely through the extended. Troughiness over the northeastern 
US will continue through the period with daily rain showers/thunderstorms and rain chances 
given cool temperatures aloft. However...psunny skies will dominate along 
with temperatures close to or a little below seasonal norms. 


&& 


Aviation /00z Thursday through Monday/... 
heavier rain has moved east of the taf sites for now. Mainly VFR 
conditions to start, with some scattered showers or a thunderstorm 
that may produce brief MVFR this evening. Overnight, expect areas 
of fog. Visibilities to diminish to MVFR/IFR as fog sets in...possibly 
LIFR at Elm/bgm. Areas of rain likely to continue through the 
night at avp. 


There is a chance for some thunderstorms to develop Thursday afternoon. 
For now, have covered with tempo or probability for rain showers with cumulonimbus groups. 


Winds gnrly light southeasterly tonight...shifting to SW/west 14z Thursday. 


Outlook... 


Thursday night through Monday...fog possible each morning...with potential 
IFR restrictions...otherwise mainly VFR. Brief restrictions 
possible in scattered showers/thunderstorms for the afternoon and 
early evening hours as ul system hangs over the region. 


&& 


Bgm watches/warnings/advisories... 
PA...Flood Watch through Thursday morning for paz039-040-043-044- 
047-048-072. 
New York...Flood Watch through Thursday morning for nyz009-036-037-045- 
046-056-057-062. 


&& 


$$ 
Synopsis...jma 
near term...jma 
short term...jma 
long term...jma 
aviation...jml/pvb