textproduct: Raleigh

SYNOPSIS

A strong cold front will sweep across the state this afternoon. High pressure building in behind the front will bring dry weather through early Friday.

NEAR TERM /THROUGH TONIGHT/

As of 1205 PM Monday...

* Red Flag Warning remains in effect until 7 pm for the Piedmont and western Sandhills

* Gusty winds 30-35 mph, infrequent 40 mph into the mid-late evening hours

Satellite and surface observations currently place the strong cold just east of the Triad as of 12pm. The cold front will continue to advance eastward, reaching the coast by early evening. Ahead and behind the front, we are still expecting a period of gusty winds into the mid to late evening hours. Gusts ahead of the front are peaking in the middle 30s mph, with post-frontal gusts in TN and western NC in the 40 to 45 mph range. These gust of 30-35, infrequent to 40 mph, will pick up post-frontal with a combination of strong CAA and deep BL mixing. Temperatures may rise a few more degrees ahead of the front over the Coastal Plain to some lower 70s, but once the front passes, temperatures will crash into the 40s later today and fall into the mid to upper 20s overnight. Wind gusts should weaken by the late evening and overnight hours, though occasional gusts in the 15 to 20 mph range are still possible as wind chills dip into the teens.

A band of light rain has developed ahead of the front over the central and northeast Piedmont and will advance east into the Coastal Plain this afternoon before exiting toward the coast by late afternoon. Rainfall amounts should generally be under a tenth of an inch.

The Red Flag Warning remains in effect until 7 pm for the Piedmont and western Sandhills for combined gusty winds and lower humidity. A further examination this morning led us to believe that perhaps conditions may not fully meet Red Flag criteria, but it is certainly warranted if dewpoints can drop faster than expected. The dry air advection looks to be a tad slower, resulting in overall higher RH than anticipated.

SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/

As of 1205 PM Monday...

* Marginal fire concerns due to 15-25 mph gusts and low humidity

* Much colder temperatures

Much colder temperatures will be in place Tue, which will feel like quite the change from the mild holiday weather. Cold high pressure over the Southern Plains will migrate slowly into the lower MS valley region. A tight pressure gradient will remain in place with deep low pressure over eastern Quebec. Highs are expected to be some 8-12 degrees below seasonal normals in the upper 30s to low 40s in the far to the middle 40s in the south.

Northwest wind gusts will certainly not be as strong as Mon but range in the 15 to 25 mph range, highest in the eastern Piedmont and Coastal Plain. Relative humidity values will be in the 25 to 30 percent range, perhaps lower 20s in the southern Piedmont. We reached out to the NCFS about a possible fire danger statement on Tue given these parameters. Currently, conditions do not appear to be as worrisome but we plan to reassess later tonight and with the NCFS on fuels and expected conditions.

LONG TERM /WEDNESDAY THROUGH MONDAY/

As of 1205 PM Monday...

* Dry weather for New Year's Eve/New Year's Day

* Temperatures returning to near normal values Wednesday through early next week

* Next opportunity for precip comes late Friday into Saturday

Broad northwesterly flow aloft will prevail through late week. While a series of weak upper level disturbances will pass by to our north across the Great Lakes and Mid Atlantic, we should only see subtle increases in cloud cover from time to time with no significant weather impacts or precip chances. Temps Wednesday through Friday will generally range from the low to mid 50s for highs, with lows in the mid 30s. The forecast for New Year's Eve should see partly cloudy skies, dry weather, and temps in the mid to upper 30s at midnight.

Meanwhile, a slow moving upper low off the southern California coast will eject a shortwave through TX into the lower MS valley on Friday. Weak height falls ahead of the trough should allow for the development of light rain across the area late Friday night, with higher precip chances likely on Saturday coincident with arrival of the shortwave itself. There is general agreement among today's 00Z/12Z ensemble clusters showing precip arriving during this time and the precip forecast is one of relatively high confidence. However the exact track of the associated surface low is still up for debate which will have impacts on the temperature forecast. Approx 2/3rds of model solutions take the surface low to our north yielding cooler temperatures across the area given northerly flow, while the remaining 1/3 of ensemble depictions take the low through VA. Will hold steady with near (or slightly below normal) temps on Saturday but if the low tracks along the coast, Saturday's highs may need to be lowered a bit. Regardless of how Saturday plays out, it appears temps should be within a few degrees of normal Sunday into Monday as conditions dry out and mid level height rises spread eastward. Highs in the mid 50s with lows in the mid 30s is well supported by today's ensemble solutions.

AVIATION /18Z MONDAY THROUGH SATURDAY/

As of 1235 PM Monday...

24 hour TAF period: The primary concern through the TAF period will be the wind. As a strong cold front comes through, gusts will increase. As of 12pm, observed wind gusts to the west of the front have not been quite as high as forecast by the models, but model soundings remain insistent that all sites should see at least 30 kt winds out of the west-northwest as the front moves through, if not approaching 35-40 kt. Did not have enough confidence to go higher than 30 kt in the official forecast, however. Have gone with prevailing MVFR to start the period at RWI, and can't rule out an isolated MVFR ceiling at RDU/RWI at the beginning of the period. Any rain along the front has been relatively light and do not expect that any showers should bring a reduction in visibility. The cold advection will be strong with this front, and while gusts normally subside around sunset, that will not be the case today. With the 18Z TAF package, have slightly delayed the drop in wind gusts from 30 to 20 kt compared to the 12Z TAF package, and have decided to keep gusts through 18Z Tuesday at all sites, even through the night.

Outlook: Dry VFR conditions are expected until Friday night, after which rain and restrictions are forecast at all terminals.

FIRE WEATHER

As of 1205 PM Monday...

* Red Flag Warning remains in effect until 7 PM to capture an elevated adverse fire behavior risk behind a cold front.

The Red Flag Warning remains in effect until this evening for the Piedmont and western Sandhills for combined gusty winds and lower humidity. A strong cold front will advance east and provide a brief window (3 hours or so) of strong gusty winds and much lower humidity, mainly over the western Piedmont. Sustained winds of 15-20 mph will gust at times to 30-40 mph. A further examination today has led us to believe that perhaps conditions may not fully meet Red Flag criteria, but it is certainly warranted if dewpoints can drop faster than expected. The dry advection looks to be a tad slower, resulting in overall higher RH than anticipated, bottoming out in the 35-percent range.

Marginally hazardous fire weather conditions will persist Tue and Wed when humidity values will be very low in the 20 to 25 percent range during the late morning through early evening hours. While humidity and fuels will meet fire danger criteria, wind gusts will be more marginal, with gusts of 15-25 mph expected. We will coordinate as needed with NCFS for any statements.

RAH WATCHES/WARNINGS/ADVISORIES

Red Flag Warning until 7 PM EST this evening for NCZ007>010- 021>026-038>041-073>077-083>086-088.