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fxus61 kakq 061158 
afdakq 


Area forecast discussion 
National Weather Service Wakefield Virginia 
758 am EDT sun Jul 6 2008 


Synopsis... 
a nearly stationary frontal boundary will remain draped across 
the middle Atlantic region...keeping unsettled weather across the 
area through Monday. The front finally pushes off the coast by 
later Monday...as weak high pressure builds in for Tuesday and 
Wednesday. 


&& 


Near term /through tonight/... 
early morning analysis depicts quasi-stationary frontal boundary 
snaking from central New Jersey into northern/western Virginia and the Tennessee Valley. 
Aloft...a closed upper low was analyzed over the Ohio Valley. Have 
updated per latest radar trends...fairly solid swath of rain over 
interior southeast Virginia and this looks to track into Northern Neck over next 2-3 
hours so have gone west/ likely probability of precipitation for these areas this morning and with 
fairly stable conds through the morning have also dropped thunderstorm coverage this 
morning to only slight chance. 


Shortwave energy associated with upper low will help to bump boundary a 
bit farther north today. Still...look for more scattered thunderstorm coverage by 
afternoon and into this evening. Either way...even in areas that don't 
get as much in the way of heavy rainfall...despite a few breaks of 
sun today...sky grids average out to mcldy conditions once again today. 
Considerable clouds and moisture should keep temperatures below climatology 
again...generally l/M 80s. 


Severe parameters remain minimal today. SBCAPE <1000 j/kg and 
0-6km bulk shear remaining in the 15-20 knots range. Still...can't 
rule out a few pulsy isolated strong to severe storms today given strong 
low level lapse rates...and MUCAPES on the order of 2000-2500 j/kg as 
per the NAM this afternoon (sig higher GFS seems to be a little 
too high...and likely suffering from some convective feedback 
issues). Wet downbursts would be the primary threat (pwats rise to 
>2 this afternoon). Accordingly...will also have to watch flash 
flooding threat given aforementioned heavy rainfall over parts of 
the area Sat. Scattered slow moving heavy rainers again a good bet 
today...and hwoakq will be updated reflect this threat. 


&& 


Short term /Monday through Tuesday/... 
upper trough slowly opens and tracks farther to the northeast by 
Monday. Have focused highest precipitation chances Monday across NE NC/far 
southeast Virginia...with somewhat lower chances elsewhere (but still above 
climatology at around 40%). Given decent low to midlvl bulk shear 
values and modest cape...Storm Prediction Center has placed entire middle-atl region in 
"see text" for Monday. Temperatures gradually rise into the 90s with 
more sun expected by Tuesday. 


&& 


Long term /Tuesday night through Saturday/... 
Bermuda high pressure builds in by Tuesday night. Kept 20% chance of 
rain showers/thunderstorms through then with the highest chance over southeast Virginia/NE NC where 
lingering moisture and forcing mechanisms from the frontal remnants 
will still be in place. Lows will be in the upper 60s in western sections 
to lower 70s in the east/coastal locations. 


Wednesday am starts out dry. An upper level trough and associated surface 
front located near the Great Lakes begins to move closer during the 
day...while the S/SW flow around the high offshore increases. 
Abundant moisture will get pumped up around the high and ahead of 
the front...so have 20% chance of rain showers/thunderstorms during peak heating 
hours. The front then sags to the south Wednesday night through Thursday night. 
Chance of rain showers/thunderstorms continues through this period as the boundary 
slowly attempts to move farther through our area. High temperatures will be in 
the upper 80s/lower 90s Wednesday and Thursday...and low temperatures will range from the 
upper 60s/lower 70s. 


The front will stall and eventually wash out across our southern counties 
on Friday. Will still have a chance of precipitation on Friday through Friday night in 
the south closest to what will be left of the boundary...with a 
slight chance farther north and west. High temperatures will be cooler on 
Friday with 850 temperatures falling to 13 to 15c and with additional cloud 
cover. Min temperatures will also drop slightly on Friday night/Sat 
am...generally 65 to 70 except lower 70s right at the southern beaches. 


&& 


Aviation /12z Sunday through Thursday/... 
MVFR to local IFR cndtns through 15z or so due to plnty of ll moisture and 
scattered showers. Could see a few hours of VFR ceilings this afternoon b4 more showers 
and tstrms develop in htng of the day. Went ahead with a tempo for 
showers next few hours (based on radar trends). Tapered off probability of precipitation this 
afternoon but indct cumulonimbus for tstrm threat. Added showers in tafs closer to 
00z. More of the same tonite as MVFR/IFR cndtns develop due to abundant 
ll moisture. 


&& 


Marine... 
winds become S and increases this afternoon due to increasing p-gradient between Lee 
trough and return flow and Bermuda ridge. Could still see a few gusts 
to 20 kts over the (srn) ches Bay aftr 19 or 20z...but any gusts 
are not expeceted to last long enough to warrent Small Craft Advisory. Otw...SW winds (aob 
20kts) continue around Bermuda ridge through most of forecast prd. Another front 
approaches region by late in the week. 


&& 


Fire weather... 
light southerly flow to continue Sunday...so smoke will continue to 
affect much of metropolitan Norfolk/Portsmouth and outlying areas. High 
relative humidity Erly this morning will have potential for 
smoke/superfog scenario. Winds should allow for some improvement 
again by midday. 


&& 


Akq watches/warnings/advisories... 
Maryland...none. 
NC...none. 
Virginia...none. 
Marine...none. 


&& 


$$ 
Synopsis...mam 
near term...lkb/mam 
short term...mam 
long term...jrl 
aviation...mpr 
marine...mpr 
fire weather...National Weather Service akq