390 
fxus62 krah 061145 
afdrah 


Area forecast discussion 
National Weather Service Raleigh NC 
745 am EDT sun Jul 6 2008 


Synopsis... 
a stationary front will remain stalled across Virginia and West 
Virginia... with high pressure off the Carolina coast. A warm and 
humid airmass across the region will result in the development of 
mainly afternoon and evening thunderstorms through Tuesday. 


&& 


Near term /through tonight/... 
as of 300 am Sunday... 


Precipitation over the northwest Piedmont will persist through the 
morning with the steady stream from northern Georgia and western 
South Carolina... precipitation more scattered over the rest of the County Warning Area. 


Not much change in the forecast through tonight... over that of 
Saturday. Upper level trough remains west of the area providing 
moisture feed through all levels. 40 to 50 knots upper level jet 
west of the region will provide good lift. Precipitation water values once 
again around 2 inches... with lifted indice's in the -3 to -6 range... cape 
1500 to 2300 j/kg. All this will add up to another active day. One 
concern today is heavy rain over the northeast... since its had 
upwards of 5 inches of rain over the past few days. Additional rain 
could lead to some flooding problems... so this area will be 
monitored for any slow moving storms. 


Highs today in the 80s to around 90 in the southeast. Lows tonight 
in the 60s to lower 70s. 


&& 


Short term /Monday through Tuesday/... 
as of 300 am Sunday... 


Moist unstable conditions continue over the area. The precipitation water 
values do lower some on Monday as winds become more southerly... 
however as winds veer to more southwest values creep back to 1.75 to 
near 2 inches for Tuesday. This combine with upper level troughs 
starting work their way across the area and a warming trend over the 
region... showers and thunderstorms will be the order of the day 
through the beginning of the work week. Highs will be in the low 
90s. Lows Monday night will be in the 60s. 


&& 


Long term /Tuesday night through Saturday/... 
as of 320 am Sunday... 


The influence of a weak surface ridge that is in place across 
central North Carolina during the day Tuesday begins to wane in 
favor of increased surface troughiness over the state by Wednesday. 
The latest GFS shows a surface trough developing and remaining over 
or near central North Carolina through the rest of the work week and 
the start of next weekend as deep moisture remains the rule over the 
forecast area. The 00z GFS has precipitable water values... 
overall...from 1.75 inches to 2 inches during the period. If the 
GFS verifies...weakly diffluent upper flow...with the moisture and 
available surface convergence...should continue to allow at least 
scattered showers and thunderstorms. The one day in this long-term 
period where the chances for showers and storms may be reduced some 
over part of central North Carolina is Thursday...when the GFS 
actually diminishes precipitable water values to only an inch to 1.5 
inches across northern zones as the upper flow becomes more 
confluent. Would not be surprised if this subtlty changes over the 
course of time and still left chance probability of precipitation in for Thursday...though 
slightly less...especially north...than Wednesday and Friday. 


Made no changes to highs and lows at this time. 1000-850mb 
thicknesses would on some days support warmer temperatures than 
currently forecast. However...this could be offset by the moist air 
mass and ample cloud cover. Surface dew points are expected to 
remain in the middle 60s to lower 70s...consistent with anticipated 
overnight lows during the period. 


&& 


Aviation /12z Sunday through Thursday/... 
as of 745 am Sunday... 


Scattered showers and isolated thunderstorms had gradually 
diminished in intensity and coverage during the early morning 
hours...while many locations outside of the sandhills and southern 
coastal plain were in IFR conditions primarily due to low clouds. 
The very moist boundary layer was coincident with the NAM bufr 
soundings which were supportive of IFR conditions in low clouds 
across central North Carolina. As mixing develops during the 
morning...ceilings should rise through MVFR and to VFR. However... 
with high precipitable water values of 1.75 to 2 inches...good 
diffluence aloft with the upper trough in place to our west... 
central North Carolina being in the right entrance region of a 
55-65kt 250mb jet...and ample instability as shown by NAM forecast 
soundings...once again expect numerous showers and thunderstorms to 
redevelop across the region this afternoon continuing into the 
overnight hours. Surface winds should tend to veer from light 
southeast to south and southwest at 10kt or less...and winds aloft 
through 3k feet should be 20kt or less. NAM bufr soundings and MOS 
guidance are not depicting as much potential for low clouds early 
Monday morning as was occurring this Sunday morning...though the 
trend for this will certainly need to evaluated further over time 
given the moist air mass and modest increase in winds off the 
surface late tonight. 


Weather pattern changes little through Monday...although 
precipitable water values will diminish slightly in The Triad. 
Aviation interests should prepare for at least scattered storms on 
Monday. From Tuesday through Thursday...there will continue to be a 
chance of showers and thunderstorms in a moist air mass. Surface 
ridging building in weakly from the east may result in a lesser 
amount of storm coverage and chances Tuesday...with a surface trough 
moving in for middle week helping to increase chances once again by 
Wednesday. If the GFS model verifies...northern taf sites may be 
drier and slightly more stable Thursday versus kfay in slightly more 
confluent flow aloft. 


&& 


Rah watches/warnings/advisories... 
none. 


&& 


$$ 
Synopsis...rhj 
near term...rhj 
short term...rhj 
long term...djf 
aviation...djf