694 
fxus61 kakq 070057 
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Area forecast discussion 
National Weather Service Wakefield Virginia 
857 PM EDT Sat Sep 6 2008 


Synopsis... 
Tropical Storm Hanna will continue to move rapidly northeast and away 
from the area tonight. High pressure builds into the middle Atlantic 
region for Sunday and Monday...while a cold front approaches from 
the northwest on Tuesday. The front will gradually drop south 
through the middle Atlantic area Tuesday night and Wednesday. 


&& 


Near term /through Sunday/... 
Hanna continues to track NE and away from the area this evening. 
Winds have since decreased to below tropical criteria, so Tropical 
Storm Warning for the rest of the forecast area has been cancelled. 


Total rain amounts have ranged from 1 to 3 inches east of I-95 (lcly 
higher amounts across portions of lower Maryland eastern shore)... with amounts 
between 2 to 4 inches over most areas west of I-95. Pockets of 5-7" 
amounts were noted over portions of the eastern Virginia Piedmont...with radar 
estimates near 8" over far western Prince Edward County. 


Clearing conditions overnight will likely lead to areas of fog... 
especially considering the amount of standing water...though the 
extent and density will depend heavily whether or not surface winds 
will decouple or not. For now...will have areas of fog mentioned... 
allowing later shifts to evaluate based on ob trends this evening. 


Other major concern is coastal flooding situation for Dorchester 
County Maryland. See coastal flood section blw and wbccfwakq for more 
details. 


&& 


Short term /Sunday night through Tuesday night/... 
high pressure builds in behind Hanna Sunday and Monday. Lingering 
tropical airmass results in a mostly sunny day with highs in the 
mid to upper 80s and lows in the 60s...xcpt for sby where improving 
radiational cooling conditions may drop min temperatures into the upper 
50s Monday morning. Will have to be mindful of possible diurnal 
development across eastern Virginia/NC along sea/Bay breeze convergent zone 
for both Monday and Tuesday...as is hinted by both the GFS/NAM. At this 
point...given the degree of anticyclonic flow and relative lack of 
low level instby/thermodynamics...have refrained from including rain 
chances in the forecasts. 


Please consult the latest tropical storm local statement from National Weather Service 
Wakefield (hlsakq) for the latest information on T.S. Hanna. 


&& 


Long term /Wednesday through Saturday/... 
GFS/European model (ecmwf) remain in decent agreement and continue to show the cold 
front stalling across the Carolinas on Wednesday as the middle level flow 
flattens out. Will have 30% chances of precipitation across the south tapered 
to dry forecast north. With north-northeast flow highs should remain in the upper 
70s. 


Difficult forecast Thursday/Fri/Sat as eventual track of Ike will be the 
dominant feature. Overall best chances for showers would be SW zones 
west/ low level Ely flow as weak warm advection begins to move back in 
the low/middle levels from the SW. Keeping 20-30% chances in forecast both 
Friday and Sat but will be subject to changes as track of Ike becomes 
more certain. Temperatures near average for Sep. 


&& 


Aviation /01z Sunday through Thursday/... 
conditions steadily improving across terminals this evening as 
Hanna pushes NE away from the region...with MVFR to VFR conditions 
across area terminals. Gusts have relaxed a bit over soutehrn 
terminals...and will continue to lessen and become less frequent 
this evening over the Tidewater/Eastern Shore. Have removed gusts 
from this taf cycle after midnight. 


Combination of wet ground...clearing skies and decoupling winds 
should make for ideal conditions for fog development overnight. Accounted 
for MVFR/IFR conditions at area terminals after 06z...with the 
possibility of short lived LIFR conditions ivof sby. Visibilities recover 
to VFR quickly after sunrise Sunday morning. 


VFR conds during the day Sunday with downsloping winds and building 
high pressure. After another night of scattered early morning fog Monday 
morning...look for VFR conditions during the day on Monday. Chance of 
precipitation increases through the day Tuesday ahead of approaching cold 
front. 


&& 


Marine... 
small craft advsy has replaced Tropical Storm Warning for all waters. 
Winds will continue to rapidly decrease later during the late eveng 
and overngt. 


Much lighter winds generally 20 kts or less after midnight and into 
Sunday morning. Weak high pressure takes control sun/Mon...then 
flow turns back to south-southwest ahead of next cold front Tuesday...with a Small Craft Advisory 
surge possible later Tuesday into Wednesday depending on how much cold air 
can make it this far south. 


All marine interests should continue to monitor the latest forecasts 
from the National Hurricane Center for information on Hanna. 


&& 


Tides/coastal flooding... 
while most areas have generally gone through the event with only minor 
tidal flooding...Cambridge is currently experiencing moderate 
flooding and with northwest flow continuing through at least 9-10 PM...severe 
flooding is anticipated from about 8 PM through 11 PM when Ater 
levels rise above 4.5 feet MLLW (see wbccfwakq for details). 


& 


Akq watches/warnings/advisories... 
Maryland...coastal Flood Warning until 1 am EDT Sunday for mdz021. 
NC...none. 
Virginia...none. 
Marine...Small Craft Advisory until 4 am EDT Sunday for anz630>633. 
Small Craft Advisory until 10 am EDT Sunday for anz650-652-654- 
656-658. 


&& 


$$ 
Synopsis...bkh 
near term...bkh/smf 
short term...bkh 
long term...lkb 
aviation...mam 
marine...lkb 
tides/coastal flooding...lkb