textproduct: Raleigh

SYNOPSIS

A weak front will generally stall over the area through Thursday, before washing out on Friday. Bermuda high pressure will then build over and off the Carolina coast into early next week, bringing warm and humid conditions.

NEAR TERM /TODAY THROUGH TONIGHT/

As of 335 AM Wednesday...

As of around 330am a cluster of thunderstorms is moving across the Northeastern Piedmont. It has been pulsing in intensity the past hour, but seems to have entered a more stable environment. These showers/storms are expected to move east/northeast over the next few hours before exiting the region just after sunrise this morning. Low stratus and patchy fog could develop in the wake of the storms so early morning commuters should take extra caution.

A weak surface boundary will remained stalled over the region today. The boundary is expected to extend from the Northeast Piedmont/Northern Coastal Plain region down SW across the CWA into the Southern Piedmont continuing through SC. While most of the day will be dry, afternoon daytime heating along with a sea breeze moving inland will result in some isolated afternoon/evening showers and thunderstorms to develop. Over the past five days the RAH CWA has been in either a Marginal or Slight risk for severe weather, today the CWA is only in the General Thunderstorm category. The best chance will be along and east of the boundary which is expected to set up over the US-1 corridor. The threat for storms should diminish in the late evening hours, with overnight through Thursday morning being dry. Temperatures will be slightly above normal with highs in the mid/upper 80s. It will feel warm and muggy east of the front with some heat indices reaching 90-92 degrees. Overnight temperatures will be in the upper 60s to low 70s.

SHORT TERM /THURSDAY AND THURSDAY NIGHT/

As of 345 AM Wednesday...

* Scattered storms possible Thursday, mainly across southern areas, as heat and humidly increase again across the area.

An increasingly diffuse frontal zone wavering across the Piedmont will essentially wash out on Thursday. Meanwhile, high pressure settling off the Carolina coast will initiate moist return flow across the southeast US under a broad upper level.

While more significant deep layer moisture return will hold off until the weekend, dewpoints creeping back into the lower 70s will result in weak to moderate CAPE. Convective trigger should include the thermally enhanced Piedmont trough and an active seabreeze, with better focus for scattered showers and storms likely to be across southern and eastern portions of the CWA.

Highs will again be near normal in the upper 80s to around 90.

Convective should be mostly diurnal and yield to a quiet but humid Thursday night with lows in the upper 60s and lower 70s.

LONG TERM /FRIDAY THROUGH TUESDAY/

As of 345 AM Wednesday...

* Chances of mainly afternoon and evening showers and storms increase through the weekend.

* Humidity values increase with surface dew points reaching the lower to mid 70s at times producing max heat index values in the mid to upper 90s and moderate heat risk across southern and eastern areas over the weekend into early next week.

An established Bermuda high and southerly return flow will send PW into the 150-200 percent of normal range over the weekend. Forcing storms will be weak, but with a weak cap and anomalously moist atmosphere, scattered to at times numerous showers and storms are possible each day into early next week. Weak mid level flow will limit a severe threat early in the weekend, though weak storm motion and high PW may present an isolated flooding threat.

A weak cut off low over the southern plains is forecast to deamplify and lift toward OH Valley early next week, which may offer some additional forcing and mid-level flow to organize storms a little more. However,the overall pattern favors low predictability of the timing of storms outside of diurnal heating, the forecast will continue to feature scattered to numerous showers and storms daily.

Highs will continue to be near normal in the upper 80s, but with the increase in humidity, heat indices are forecast to creep to near 100 and the Heat Risk becomes moderate over the weekend, particularly in the coastal plain.

AVIATION /10Z WEDNESDAY THROUGH SUNDAY/

As of 635 AM Wednesday...

A round of showers moved across the northern Piedmont early this morning leaving behind sub-VFR (mainly MVFR and IFR) ceilings at RDU and RWI. While the Triad sites are VFR have a TEMPO until 14z for possibility of reduced visibilities and MVFR-IFR conditions as they also received a good amount of rain last night. As of the 9z ob from GSO shallow fog is being reported. After this lifts expect VFR conditions through the day as the surface boundary remains east of these sites. At the other 3 eastern sites, RDU/FAY/RWI all sites are sub-VFR this morning with 400-800 ft ceilings. These ceilings should lift in the next couple hours and all sites should be VFR through early afternoon. As the lingering boundary lies along the US1 corridor, expect isolated showers and storms to develop this afternoon and evening. Most of the shower/storm activity should be done by around 00z/01z with mainly VFR conditions returning overnight. Depending how much rain the region gets this afternoon and evening expect another round of fog and low stratus to develop early Thursday morning.

Outlook: As the stalled front lifts back north across the area mid- day Thursday, chances for afternoon and evening convection will return through the weekend, accompanied by the usual sub-VFR restrictions. Early morning fog and low stratus will also be possible each morning, especially at locations where rain occurs.

RAH WATCHES/WARNINGS/ADVISORIES

None.