807 
fxus61 kbox 050423 
afdbox 


Area forecast discussion 
National Weather Service Taunton Massachusetts 
1225 am EDT Sat Jul 5 2008 


Synopsis... 
above normal temperatures will prevail for most of the next week. 
There will still be the more than usual episodes of afternoon and 
evening thunderstorms associated with weakening frontal systems 
crossing New England...running into the persistent large and 
stationary west central Atlantic Ocean high pressure center. 


&& 


Near term /until 6 am this morning/... 
noting area of showers moving into S coastal CT and Li sound from 
03z-04z...along with batch of showers/thunderstorms well S of Nantucket. Both 
areas are moving east. Expect showers to develop through night from 
about a kbdl-kpvd-kpym line southward. Appears most if not all 
convection absent with the CT/Li sound precipitation /see a few c/g lightning 
strikes S of Nantucket/...so have removed thunderstorm wording through the 
rest of the night for the region. Only worry is if an isolated cell 
makes it into the cape and islands...but will monitor. Have kept 
highest probability of precipitation for S coastal areas...with chance probability of precipitation as far north as the 
Mass Pike by 09z. 


Most locations reporting light fog...with a few spots below 3 miles 
at 04z. Patchy fog already in forecast for most areas...and kept this 
going. 


Infrared satellite showing middle-high clouds...what appears to be debris 
from middle Atlantic action...moving across region...so have used either 
mostly cloudy or cloudy wording. 


Also adjusted temperatures a bit to keep a little warmer than previous 
thinking. 


&& 


Short term /6 am this morning through 6 PM Sunday/... 
muggy unsettled conditions expected through the period. 


Models indicate a pulse of Omega will continue to move northward 
into region during Sat...although there are timing differences. We 
leaned toward GFS which shows 850 mb low and associated low level jet 
resulting in area of convergence moving quickly across coastal southern New England 
late tonight into Sat morning. We kept probability of precipitation in chance range south of 
the Pike through tonight...increasing to likely near the coast on 
Sat as it appears bulk of convergence/lift will occur Sat morning. 
Convective parameters suggest thunderstorms will be possible near the South 
Coast. 


Further north...we will have just chance probability of precipitation but it may stay dry north 
of Route 2 region. Confidence is low as European model (ecmwf)/UKMET do bring quantitative precipitation forecast 
northward into New Hampshire but went dry SW New Hampshire for now. Later forecasts may need 
refinement. 


Mostly cloudy skies should prevail across much of the region Sat with best 
chance for sunshine across the far north like today. Warmest temperatures 
Sat should be in the north with readings near 80...but undercut mav 
temperatures across the coastal plain where temperatures should hold in the lower 
70s due to clouds and showers. Forecast confidence for temperatures is low. 


It appears surface front and associated deepening moisture will try to move 
back northward into region late Sat night but confidence in details 
is low. Followed mav guidance which brings chance probability of precipitation south of Route 
2 late Sat night. 


&& 


Long term /Sunday night through Friday/... 
at the very least there will be diurnal showers and thunderstorms 
through the middle of next week if not beyond. 


The severe threat for Sunday has diminished quite a bit. The 
instability just doesn/T appear to be there in any of the models. 
The sref does indicate a low probability of over 1000 j/kg of cape 
but that is the most of any model. Showers and a few thunderstorms 
are possible...especially Sunday afternoon and early evening. 
However...the main threat will be lightning and heavy rain given 
that precipitable water values are still over 1.5 times the norm. Highs will 
creep up a few degrees Sunday. Low temperatures will be a bit 
warmer with temperatures generally around 70. 


Monday and Tuesday...looks like at the very least there will be 
diurnal showers and/or thunderstorms on Monday as some shortwave 
energy moves through southern New England. Highs will warm a few 
degrees over Sunday/S highs bringing temperatures into the middle 80s. 
Tuesday will be a hot day with 2m temperatures up around 90f and 850mb 
temperatures 17-18c. High temperatures in the low 90s are possible across 
much of the area. Because of the warm surface temperatures...lapse 
rates will be quite steep. So...even though Tuesday is looking to 
be a fairly dry day...cannot rule out some diurnal shower activity. 


Overnight between Sunday and Tuesday...patchy fog is likely to 
form...especially where there have been showers/thunderstorms during 
the day. 


Sometime around middle week...the Middle Range models are predicting a low 
pressure system moving through southern Canada and dragging a cold 
front through southern New England. When this does move through... 
there is a good chance that we/ll have another round of showers and 
thunderstorms to go along with it. Exactly when this will happen 
remains to be seen. Depending on the timing of the front we could 
have one or two more hot days before temperatures cool off with the 
front. 


&& 


Aviation /04z Saturday through Wednesday/... 
overnight...expect MVFR-IFR ceilings for many areas near the coast with 
onshore flow...as well as over the CT valley. Kack already down 
to LIFR with onshore flow at 04z...not expecting much improvement 
there. Over S New Hampshire...low clouds and patchy fog will be the rule. 
Expect MVFR-IFR visibilities with fog for many areas. 


Saturday...low pressure approaches with clouds along and south of 
the Mass Pike and rain into bdl-pvd and fmh-hya-ack. Will have IFR 
in rain areas and MVFR ceilings bos-orh-bdl. Mht is north of the moist 
flow and so will likely remain VFR. 


Outlook...Saturday night through Wednesday... 


Sat night...conditions likely lowering to MVFR/IFR in areas of low 
clouds and fog. Showers possible especially south of the Pike. 


Sunday through Monday...mainly VFR with conditions degrading to MVFR 
in showers and thunderstorms in the afternoons. Overnight...patchy 
fog may lower visibilities to MVFR at times. 


Tuesday...VFR. 


Wednesday...there is a possibility that a weak cold front may move 
across southern New England. If this occurs...expect a sharp wind 
shift to the west as well as shower/thunderstorm development along 
the front. This could reduce conditions to MVFR. Otherwise...VFR 
likely. 


&& 


Marine... 
offshore buoys finally reporting below 5 feet...with 3-4 foot waves at 
44018. Swell period also down...though Marthas Vineyard Ferry still 
noted 2-3 foot SW swell on their runs tonight in the sound. 


Expect a generally light east-southeast flow as the front remains near or just 
S of the South Coast overnight. Only thunderstorms seen are well S of 
Nantucket...but another area of showers moving out of Li sound...so 
expect more visibility restrictions in showers and fog. Could lower to 1 
mile or less. 


Sat...fast moving low level jet associated with 850 mb circulation may bring a 
brief g20 kts to outer waters...otherwise easterly winds should 
become westerly after surface wave passes by. Seas 2-4 feet over open 
waters. Patchy fog may persist and cant rule out a few thunderstorms over 
south coastal waters. 


Sat night...SW winds generally under 10 kts with seas 2-4 feet over 
open waters. More fog likely. 


Outlook...Sunday through Wednesday... 


Sunday...seas below Small Craft Advisory criteria. Overnight fog may again reduce 
visibilities to 1 to 3 nm along the coast. 


Monday...seas may reach Small Craft Advisory conditions on the outer waters due to 
persistent south/southwest flow. This will also prompt the return 
of an above normal rip current risk along the south coastal beaches. 


Tuesday and Wednesday...seas continue around 5 to 6 feet across the 
southern outer waters. Above normal rip current risk may also 
continue along the south coastal beaches. 


&& 


Box watches/warnings/advisories... 
CT...none. 
Massachusetts...none. 
New Hampshire...none. 
Rhode Island...none. 
Marine...none. 


&& 


$$ 
Synopsis...kjc/rlg 
near term...evt 
short term...kjc 
long term...rlg 
aviation...wtb/evt 
marine...kjc/evt/rlg 

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