Weather

463 
fxus61 kakq 060753 
afdakq 


Area forecast discussion 
National Weather Service Wakefield Virginia 
353 am EDT Monday Oct 6 2008 


Synopsis... 
a weak cold front will push south across the area today and 
tonight. Strong high pressure builds into the middle Atlantic region 
from eastern Canada Tuesday through Wednesday. An area of low 
pressure will develop and move across the southeast states 
Thursday through Friday. 


&& 


Near term /through tonight/... 
high pressure centered over southern Ontario continues to ridge down 
into the middle Atlantic...while a poorly defined stationary front is 
draped across southern Virginia. Patchy fog continues to form early 
this morning under clear skies and light winds...with dissipation 
expected shortly after sunrise. Farther to our north an upper 
level trough and associated surface front is clearly evident on infrared 
satellite imagery...extending from the New England coast back 
across the upper Great Lakes. This feature will drop south through 
the middle Atlantic as a backdoor front later today into tonight. All 
models (except akq wrf) show a dry frontal passage with weak forcing and 
limited moisture so do not expect any precipitation. High temperatures will 
be predominantly a few degrees above normal again today in advance 
of the front...with middle/upper 70s expected. Only exception will be 
at the beaches and Eastern Shore where north-northeast flow off of the cooler 
Atlantic waters will keep highs in check (lwr 70s). 


Much cooler air arrives behind the front in earnest tonight as 
strong high pressure begins to build down from eastern Canada. Low 
temperatures will range from the middle 40s to middle 50s (even upper 30s 
in vicinity of sby). 


&& 


Short term /Tuesday through Wednesday/... 
colder air continues to filter in during the day Tuesday...and high 
temperatures will struggle to warm beyond the upper 60s/lower 70s 
under continued north/NE flow. Low temperatures also cooler Tuesday 
night...lower 40s to lower 50s. 


The high will move overhead and eventually slide off the middle 
Atlantic coast on Wednesday as a developing area of low pressure and surface 
front approach from the W/SW. Winds weaken and become southeast/S as the 
high translates offshore...and high temperatures will warm closer 
to normal values...lwr/mid 70s. 


&& 


Long term /Wednesday night through Sunday/... 
will continue to follow HPC extended solution and lean toward the 
slower European model (ecmwf) (due to better continuity). GFS remains the outlier 
and therefore is discounted although latest run is beginning to 
trend more towards model consensus. 


The low pressure systm closes off across the miss vlly late Wednesday. 
Systm then prognosticated to slowly track east into southern middle atlntc region Thursday 
then to coastal sctns Friday. Still a lot of uncertainty on how this 
evolves...but appears that best chance for precipitation with this systm 
across forecast area will be Thursday afternoon through Erly Friday. Aftr that...plnty of 
moisture prognosticated to linger across region as moist east flow develops between high 
prs to the north and coastal trough to the S to continue chance probability of precipitation into next 
weekend. Temperatures rthr tricky as well. If we get socked in with overcast 
skies and precipitation...readings will likely not get out of the 60s 
Fri/Sat. For now...will keep highs gnrly in the l-M 70s with lows 
between 50-60. 


&& 


Aviation /07z Monday through Friday/... 
patchy fog continues through approximately 12z...overall expect it 
to be most widespread for interior southern/central zones where moisture 
dew points are somewhat higher...particularly ecg. Winds/mixing will 
allow fog to dissipate leaving VFR conditions today...and rather dry 
airmass tonight should limit any nighttime fog development. VFR 
conditions continue Tuesday/Wednesday aside from patchy fog Wednesday morning. Next 
decent shot for rain and widespread lower ceilings/visibilities may come later 
Thursday associated west/ low pressure approaching from the SW. 


&& 


Marine... 
weak boundary dropping through the waters Erly this morning...with 
winds shifting to the north-northeast. Although winds will pick up a bit...they 
look to remain below small craft advsy levels through the day as 
cold air surge remains well off to our north. 


This evening...have small craft advsy flags raised for all zones as 
850 mb temperatures drop significantly...leading to better mixing of 
wind gusts down to the warmer water surfaces. This looks to be a 
rather quick shot of higher winds...with high pressure rapidly 
building over the waters by late Tuesday morning/Erly afternoon. Have 
adjusted the small craft headlines to end at 13-16z Tuesday for Bay and 
coastal waters north of Cape Charles Light. Farther south the gradient is 
a bit stronger and a longer fetch will build the seas to around 6 or 
possibly even 7 feet by Tuesday morning...with seas likely staying at or 
above 5 feet through the day Tuesday. 


High pressure then remains in control Tuesday night/Wednesday with lighter winds 
and lower seas. Uncertainty with next system Thursday/Friday but overall 
expect seas to increase somewhat as flow becomes southeast or east. 


&& 


Akq watches/warnings/advisories... 
Maryland...none. 
NC...none. 
Virginia...none. 
Marine...Small Craft Advisory from 7 PM this evening to 12 PM EDT 
Tuesday for anz632-633-650-652-654. 
Small Craft Advisory from 7 PM this evening to 9 am EDT 
Tuesday for anz630-631. 
Small Craft Advisory from 7 PM this evening to 6 PM EDT 
Tuesday for anz656-658. 


&& 


$$ 
Synopsis...jrl 
near term...jrl 
short term...jrl 
long term...jrl/mpr 
aviation...lkb 
marine...lkb