textproduct: Raleigh

WHAT HAS CHANGED

* Nothing appreciable

KEY MESSAGES

As of 300 AM Friday...

1) Hot, but with low humidity, and dry through Sunday

2) Largely diurnally driven convection possible each day through mid week

DISCUSSION

As of 300 AM Friday...

KEY MESSAGE 1... Hot, but with low humidity, and dry through Sunday

A mid-level anticyclone over the TN and lwr OH Valleys will drift slowly across the Southeast and reach the FL peninsula and nern Gulf by the end of the weekend.

At the surface and through the same time, a continental/Canadian- sourced high now just offshore the Carolinas will drift toward Bermuda while continuing to extend wwd and into the South Atlantic states, while a trough will sharpen in the lee of the srn and cntl Appalachians and precede pre-frontal convection and outflow that may drift from VA Sun to nrn NC by Sun evening and a backdoor, synoptic cold front that will probably settle across cntl NC on Mon.

Subsidence and sswly low-level flow related to the sub-tropical ridging, and also increasingly wly/downslope flow over NC by Sun, will yield hot temperatures throughout the period, hottest Sun. Min RH will remain quite low, however, and mostly in the 20s percent, owing to unseasonably low mixed dewpoints each afternoon that will increase about 5 F each day, from upr 40s to around 50 F today to upr 50s to around 60 F by Sun. Heat index values will consequently be lower than the ambient air temperature and well shy of heat- related headlines. Experimental Heat Risk is nonetheless forecast to increase from Minor-Moderate today to Moderate-Major by Sun, with impacts mainly to those sensitive to heat.

KEY MESSAGE 2... Largely diurnally driven convection possible each day through mid week

Aloft, the sub-tropical ridge will amplify from the Southeast to the Great Lakes Sun/Sun night, situated between a departing s/w clipping the mid-Atlantic coast and another lifting nwd across the Plains/MS Valley. The ridge will gradually break down through mid-week as the s/w to the west progresses ewd across the upr MS Valley and Great Lakes. The ridge should once again strengthen to the west as the s/w slides sewd from the Great Lakes across the Northeast and mid- Atlantic Thu/Fri. At the surface, a backdoor cold front will slide sswwd across the area Sun night/Mon. Guidance varies wrt the strength and location of the high as it settles sewd along/off the mid-Atlantic/Carolina coast Tue/Tue night and how much/long the high/ridge lingers. Generally expect the high to shift offshore by Wed/Wed night, but linger somewhere between the East Coast and Bermuda through Thu. While there is still uncertainty wrt the chances and coverage of convection, there will be at least a slight chance for largely diurnally driven convection each day. The highest chances will be Mon and Thu with the shortwaves clipping the region. As for temperatures, Tue will be the coolest day, with highs in the mid/upr 80s, then moderating back into the low/mid 90s by Thu. Little overnight relief, with lows generally in the low/mid 60s Mon/Tue and upr 60s/low 70s Wed/Thu.

AVIATION /11Z FRIDAY THROUGH TUESDAY/

As of 645 AM Friday...

Dry air related to high pressure just offshore the Carolinas will maintain VFR conditions and direct across cntl NC light swly surface flow that may occasionally gust into the mid teens kts this afternoon.

Outlook: A backdoor cold front will settle into cntl NC with both a chance of showers/storms and a band of post-frontal, MVFR ceilings late Sun night through Mon.

CLIMATE

Record High Temperatures:

June 7: KGSO: 98/1925 KRDU: 100/2008 KFAY: 99/2008

June 8: KRDU: 101/2008 KFAY: 101/2008

Record High Minimum Temperatures:

June 7: KGSO: 73/2008 KRDU: 74/2008 KFAY: 75/2008

June 8: KGSO: 73/2008 KRDU: 75/1899 KFAY: 74/2008

RAH WATCHES/WARNINGS/ADVISORIES

None.