Key MESSAGE 1, Strong, but slow-moving, cold front is entering the northern-most portions of our FA. Disorganized shortwave energy over the Northern Plains phases over the Great Lakes and digs across the mid-Atlantic. Mid- level heights remain well above average for late March (up to 1-2 sigma), with low level thicknesses supporting highs in the mid to upper 80s inland. This will threaten a few record highs - see the CLIMATE section for details.
KEY MESSAGE 2, Increased moisture advection along the southward-advancing frontal zone looks to support the next appreciable chance of showers and an isolated thunderstorm or two, focused mainly tonight into Saturday, with the best chances north of US Highway 70. Weak instability and rather stubborn convective inhibition, makes the severe thunderstorm risk very low (less than 2%). Latest RAP analysis shows less than 300 J/kg CAPE across the bulk of the FA, but there is a small pocket of 500 J/kg CAPE immediately ahead of the seabreeze with some energy and moisture pooling. Best chance for any thunder lies where the seabreeze collides with the front and offshore over the warmer GStream waters. Any tstorm that does develop will not be long lived though. Further inhibiting thunderstorm chances is the anafrontal nature of this boundary, with the bulk of precipitation expected to fall on the cooler, more stable side of the front.
Overall moisture does not look to be deep enough to support significant rainfall, although several 12z models are showing higher QPF amounts to around a quarter inch with some HiRes models showing up to a half inch. Highest amount still appear to be across the northern tier.
KEY MESSAGE 3, Behind this front, another surge of northerly winds is expected tonight and Saturday, along with cooler, below normal temperatures returning over the weekend. There is a potential for frost Saturday night with latest NBM probs showing greater than 70 percent across inland counties, and north of 80 percent along and north of Highway 64. Frost has been added to the WxGrids, but no headline has been issued yet. Coldest MinTs may reach at or just below freezing over far inland areas albeit not for an extended period of time, around 3hrs or less. Should the forecast get any colder, Freeze headline may be needed for the NWern-most zones in the FA.
KEY MESSAGE 4, A deep, and dry, northerly flow will develop across the Carolinas on Saturday, and is expected to RH values falling into the 20s. This will overlap with breezy conditions, leading to an increased fire danger for roughly the western half of ENC. In coordination with the NCFS, an Increased Fire Danger Statement (IFD) will be issued for Saturday to cover the this risk. Across the Outer Banks, the cool and more moist onshore flow off the Atlantic should limit the fire danger, and the IFD will not include those areas for now. Of note, portions of the IFD area could come close to critical fire concerns (ie. Red Flag Warning criteria). This may especially be the case if the winds end up higher and/or if the RH ends up lower.
00z Saturday through Wednesday As of 8 PM, Cold front was stretched west to east generally from KISO to KEWN, with rapid wind switch to nerly behind the front. Gusty NE winds this evening become N on Sat, with gusts in the 20-25 kt range expected.
Post frontal rain is expected this evening, with best coverage at KPGV where several hours of pvlg rain in fcst, Showers are more spotty further south with lessening moisture, but can't rule out a few hours of rain even at EWN and OAJ.
Outlook (Sunday through Wednesday): High pressure will move over the region this weekend, then shift offshore by next week. As the high shifts offshore, moisture return may support afternoon cumulus development along the seabreeze, with brief bouts of MVFR/low VFR CIGs, and some tempo BR during the overnights/early morning hours.
Sca criteria winds and/or seas are present across all inside and outside waters as cold front enters the FA. Sw flow S of the boundary that will slowly sink Sward across the waters through this evening with a strong Nerly surge developing behind it. The strongest CAA will occur after midnight through much of Saturday when Gale Force conditions are expected with highest chances across the coastal waters and Pamlico Sound. Seas will build to 6-10+ ft peaking during the day Saturday.
Marine headlines have been updated to upgrade pre-existing Gale Watches to Warnings with all other SCA remaining in place.
Outlook: Seas will likely remain elevated into at least Sunday. Mostly benign conditions expected for much of next week with high pressure centered off the coast.
Nc, none. Marine, small craft advisory until 8 pm EDT Saturday for amz131-136- 137-230-231. Small craft advisory until 4 am EDT Saturday for amz135-152- 154-156-158. Gale warning from 4 am to 6 pm EDT Saturday for amz135. Small craft advisory until 8 am EDT Saturday for amz150. Gale warning from 8 am to 4 pm EDT Saturday for amz150. Gale warning from 4 am to 8 pm EDT Saturday for amz152-154-156- 158.
