textproduct: NWS Wilmington

WHAT HAS CHANGED

Concern for adverse fire weather conditions later this week has increased. Aviation discussion updated for 12z TAFs.

KEY MESSAGES

1) Persistent dry weather and near-record warm temperatures may create fire weather hazards this week.

2) A cold front expected to arrive next Sunday will bring a low chance of showers and a cooler airmass early next week.

DISCUSSION

KEY MESSAGE 1: Persistent dry weather and near-record warm temperatures may create fire weather hazards this week.

A 500 mb ridge centered across Florida should expand northward over the next couple of days, leading to continued dry weather and above normal temperatures across the Carolinas. Ridging aloft will support Bermuda high pressure off the East Coast through the period. Model trends over the past 24 hours have shown essentially no change with the predicted 500 mb pattern or predicted 850 mb temperatures, leading to a forecast that looks almost identical to what we constructed this time yesterday. A weak upper trough passing by to our north on Friday could lead to a few more clouds, but warm and dry mid levels should keep the weather dry.

High temperatures have a reasonably good chance of reaching 90 degrees inland on Wednesday, then exceeding 90 degrees on Friday and Saturday. Along the coast, south to southwest synoptic winds plus the afternoon seabreeze should keep high temperatures ~5 degrees cooler in Wilmington and ~10 degrees cooler at the beaches compared to inland areas.

SPC has included a portion of the Carolinas in their Fire Weather Outlook for Wednesday citing low humidity, a moderate southwest wind, and a unusually high Energy Release Component (ERC: an index utilizing fuel moisture to indicate how energetically heat will be released by burning woody fuels.) Our current forecast has relative humidity bottoming out in the 25-30 percent range along the Interstate 95 corridor Wednesday. Similar conditions are expected again Friday and Saturday.

Record highs coming up later this week: .............Wed Apr 15...Thu Apr 16...Fri Apr 17...Sat Apr 18 Wilmington......92 in 2006...90 in 2006...89 in 2006...93 in 1976 Lumberton.......92 in 2006...93 in 1941...91 in 2006...91 in 1941 Florence........94 in 2006...90 in 2006...93 in 2006...93 in 1981 N Myrtle Beach..90 in 2006...87 in 2006...87 in 1995...89 in 1976

KEY MESSAGE 2: A cold front expected to arrive next Sunday will bring a low chance of showers and a cooler airmass early next week.

An upper trough pushing eastward across the Great Lakes Sunday will push a surface cold front into the Carolinas on Sunday. The latest GFS, Canadian, and ECMWF all show the front moving through during the afternoon hours, but also show only a tenuous and fading connection to any Gulf moisture. Precipitation along the front may be limited to just a smattering of showers or storms with 0-6 km bulk shear possibly too large for the limited moisture and instability present.

Among the dozens of model ensemble members within the NBM, about 30 percent of them show at least .01" of rain across the area associated with Sunday's frontal passage. Increasing the PoP threshold to .10" cuts this to around 20 percent. This system appears unlikely to meaningfully alleviate deteriorating drought conditions across the area.

The biggest impact from this front should be the arrival of a cooler airmass for Sunday night into Monday. Monday's predicted highs are in the lower to mid 70s, near to slightly below normal for mid April.

AVIATION /12Z TUESDAY THROUGH SATURDAY/

VFR will prevail through 06z TAF period. Have kept any restrictions out of the TAFs. Intermittent high clouds through tomorrow. Winds will remain S-SW. Winds will back slightly and increase with gusts up to 25 kts or so in strong afternoon seabreeze. Increased confidence that brief early morning fog development should not affect the terminals heading into Wed due to slightly lower moisture and a bit stronger winds.

Extended Forecast...Predominantly VFR through the week due to high pressure. Only exception could be some MVFR or even IFR fog heading into sunrise each morning.

MARINE

Through Tonight...Bermuda high pressure will remain in control with predominantly SW winds in place. Winds will back slightly in the afternoon to a more southerly direction and become gustier and increase in afternoon sea breeze. Overnight into early morning the winds will veer to a more SW direction and lighten. Seas will be 2 to 4 ft with an increasing southerly wind wave in the afternoon and a longer period ESE swell mixing in.

Wednesday night through Saturday...Bermuda high pressure off the East Coast will maintain a south to southwest wind along the Carolina coast through Saturday. Synoptic winds should average 10 to occasionally 15 knots with afternoon seabreezes expected to create localized increases to almost 20 knots during the afternoons and evenings. It's a very summerlike pattern.

An east-southeasterly Bermuda swell at a 9 to 10 second period will continue through Saturday, topped off by short period wind chop that could become rough for kayakers and small boats during the afternoons and evenings. Within 20 miles of shore combined seas should average 2-3 feet.

ILM WATCHES/WARNINGS/ADVISORIES

NC...None. SC...None. MARINE...None.