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Area forecast discussion 
National Weather Service Buffalo New York 
939 am EDT sun Jul 6 2008 


Synopsis... 
high pressure off the Atlantic coast will keep dry weather over 
western and central New York through Monday. A cold front is then 
expected to slowly drop across the Great Lakes Tuesday and Wednesday 
along with a chance of showers and thunderstorms. Following the 
front...high pressure and dry weather will build back across the 
area during the remainder of the week. 


&& 


Near term /through tonight/... 


10 am update...current forecast and grids in great shape...just 
tweaked sky cover a bit as well as slight chance probability of precipitation up a little 
further northwest later this afternoon. Dew points a bit higher than earlier 
expected and subtle short wave evident on WV loop over northern wva/southeast Ohio 
lifting north and should serve to help advect moisture northward 
across western PA and into SW New York this afternoon. Will need to keep an 
eye on this if flow turns NE along the Lake Erie shore and creates a 
good convergence zone between it and the south-southeast flow inland. This is 
where any convection would pop if it does indeed occur. Rest of 
previous disc left alone and follows... 


Our beautiful Holiday weekend weather will continue through today 
as a weak high...centered over New York state remains in control. 
The impact from the Tennessee Valley upper level trough should be 
minimal for our area as this feature continues to track farther to 
the south. The combination of daytime heating and increasing 
dewpoints will result in an increase in surface based convective available potential energy during 
the afternoon...especially across the southern tier and upper 
Genesee Valley. The nam12 surface wind fields do show weak lake 
breezes forming off lakes Erie and Ontario during the afternoon. 
As these lake breezes converge with the weak southerly gradient 
wind...some moderate cumulus may form. Therefore...will leave in the 
slight chance probability of precipitation across the southern tier and upper Genesee 
Valley to account for any isolated convection that may pop up. 


Area temperatures should have no problem warming into the middle 80s 
today as 850 mb temperatures climb to about 16c. 


The organized diurnal cumulus will dissipate shortly after sunset...but a 
few SC may linger across the southern tier overnight as several vorticity 
lobes shear out from the Tennessee Valley upper low. Expect a return 
to more muggy conditions tonight as dewpoints rise into the lower 
and middle 60s. This will also increase the chances for some fog across 
the southern tier valleys. 


&& 


Short term /Monday through Wednesday/... 
dry weather should continue Monday as high pressure remains along 
the Atlantic coast, but it will be middle Summer with highs in the middle 
to upper 80s, and dew points in the middle 60s. 


A slow-moving cold front over the central Great Lakes on Monday 
should begin pushing into southern Ontario Monday night, and we have 
followed both the NAM and GFS and held the precipitation off until 
during the day Tuesday. The cold front is forecast to sag slowly 
south across the Great Lakes Tuesday and Wednesday with some 
convection ahead of it. The GFS shows the front crossing the area 
late Wednesday when we have 50% probability of precipitation. Temperatures will retreat to 
seasonal normals Tuesday and Wednesday with the precipitation, and 
it will be moderately humid with dew points in the middle to upper 60s. 


&& 


Long term /Wednesday night through Saturday/... 
high pressure cooler drier air follows the following the front on 
Thursday with the GFS showing 850 mb temperatures around +8, we have 
highs only in the lower 70s. 


A warming trend is expected through Friday and Saturday as the axis 
of the surface ridge shifts to our east...and upper ridging builds 
back across the Great Lakes. Temperatures should rise back into the 
lower 80s, with pleasant humidity levels. 


&& 


Aviation /14z Sunday through Thursday/... 
VFR conditions will be the rule today as a weak ridge of high 
pressure over eastern New York remains in control. There will be 
more widespread cumulus...however...as dewpoints rise into the upper 
50s/lower 60s during the afternoon. Weak lake breezes will also 
set up during the afternoon. The combination of daytime heating 
and convergence along the lake breeze boundaries may generate 
isolated convection this afternoon...especially across the 
southern tier and parts of the Genesee Valley where surface based 
convective available potential energy will likely exceed 1000 j/kg. 


Will also have to keep and eye on a middle level short wave that is 
advancing across West Virginia this morning. This upper level 
impulse will maintain scattered-broken VFR decks through this evening as it 
tracks north across New York state. 


Expect more fog to develop across the southern tier valleys tonight 
as dewpoints continue to rise through the 60s. This will result in 
MVFR visibilities at many southern tier locations...along with the 
possibility of conditions lowering to IFR where the fog becomes more 
widespread. 


Outlook... 
Monday...VFR after patchy early morning fog Burns off. 
Tuesday and Wednesday...VFR/MVFR in showers and thunderstorms. 
Thursday...VFR. 


&& 


Marine... 
high pressure will remain ridged across the Great Lakes through 
tonight...before shifting off the Atlantic coast Sunday and Monday. 
This will result in light winds through Monday...onshore during 
the afternoons. The next threat of thunderstorms will likely hold off until 
Tuesday and Wednesday...when a cold front is forecast to slowly 
approach and cross the region from northwest to southeast. Winds 
will increase ahead of the front Tuesday, but at this time it 
appears waves will remain below Small Craft Advisory levels. 


&& 


Buf watches/warnings/advisories... 
New York...none. 
Marine...none. 


&& 


$$ 


Synopsis...apb 
near term...sfm/tjp 
short term...apb 
long term...apb 
aviation...tjp 
marine...apb