Swell Matrix

Area Forecast Discussion

National Weather Service Newport/Morehead City Nc

245 am EDT Tue Mar 20 2018


A warm front will lift north across the area tonight with low pressure developing along it. The initial low will move northeast Tuesday but another low will move across the area Tuesday night into Wednesday. High pressure will then build in from the northwest through the end of the week.

Near Term

Until 6 am this morning As of 925 PM Monday, No changes planned to fcst. Best cvrg of shra next few hrs will be near cst with more sct activity further W. Later tonight area of shra and a few tsra expected to spread in from the W. Svr threat looks very slim thru daybreak with models keeping bulk of instab off the coast, HRRR also show organized line of storms passing well to the S late.

Prev disc, Very complicated forecast the next 48 hours. Tonight a warm front will lift slowly north across Eastern NC. Initially think precipitation will be scattered through the evening with better forcing accompanying the warm front as it accelerates northward after midnight. The models continue to indicate a triple point low forming along the front over the NC Piedmont. Precipitation is expected to increase in coverage and intensity, especially across the northern half of the area at this time with some thunder possible. Some of the higher resolution models indicate that the convection could become organized with a low end severe threat 8-14Z especially across the north but we are not outlooked by the SPC at this time and will continue to monitor. Lows temps will occur this evening but then readings should begin slowly rise late most locations as southerly flow develops in the warm sector.

Short Term

6 am this morning through 6 pm Wednesday As of 415 PM Monday, There could be a low end severe threat early in the morning with the bulk of the precipitation moving offshore around 14Z. Then there should be a couple of hour lull from late morning through early afternoon. The models bring a cold front into coastal plain and north coast by mid morning as the initial low moves off the VA Capes. There is strong agreement in the guidance that convection will rapidly develop across especially eastern portions of the area after 18Z. This will be occurring as a shortwave trough approaches the area and bulk shear is supportive of sustained updrafts with enough CAPE to support organized convection. Think the main threats will be large hail and damaging wind gusts although an isolated tornado can't be ruled out. The SPC has the "Enhanced" outlook just to our south with a "Slight" outlook across the southern half of the area and a "Marginal" outlook across the north. Areas to east of the cold front should warm into the low 70s before the storms begin.

Long Term

Wednesday night through Monday As of 415 PM Monday, Tuesday night through Wednesday night, The upper trough strengthens during this period into a closed mid level low center which is progged to move across the mid Atlantic Wed and then off of the coast Wed evening. Tue evening mid level drying should cause a temporary end to the precipitation with rain redeveloping late at night and Wed as the base of the upper trough rotates overhead. Secondary surface low pressure development is expected off the NC coast Tue evening with the low moving slowly NE just off off the east coast through Wed evening. As the secondary low strengthens off the east coast; deep wrap around moisture will coincide with CAA, leading to a transition of rain to a rain/snow mix, especially for the coastal plains late Wed. Best chances to see wintry mix Wednesday night into Thursday morning. At this time not forecasting snow accumulations, but will continue to monitor.

Expect highs in the upper 50s to low 60s Tuesday. Temperature will drop into the 40s Wednesday. Overnight lows will drop each night with lows in the upper 30s/around 40 inland and low 40s along the OBX Tuesday night. Wednesday night expect lows in the low to mid 30s inland and mid 30s along the OBX.

Thursday through Sunday , Conditions will improve Thursday as drier airmass filters in as high pressure builds in from the NW and lasting through Friday. Models are showing another low pressure system developing over the central plains, and progged to move west and north of the area. This system will bring an increase showers across the region this weekend with high pressure build behind the departing low.

Expect highs in the in the low 50s inland and mid/upper 40s OBX Thursday. Temperatures will increase each day; ranging in the 50s across the area, except OBX where temperatures will range in the upper 40s/low 50s. The coldest night this week will be Thursday night with lows in the low/mid 30s inland and upper 30s along the OBX. Then overnight temperatures will increase each night, except Sunday with temps ranging mid 30s to low 40s Friday and Sunday night and mid/upper 40s Sat night.


07z Tuesday through Saturday Through 06z Wednesday As of 200 AM Tuesday, Complex surface and upper level pattern will lead to somewhat complicated forecast during TAF period. Se winds ahead of warm front lifting up from south has lead to IFR stratus developing at all but KOAJ past few hours and lower CIGs expected to persist overnight. Widespread rain shield with a few embedded tstms will move over area from west to east mainly 08Z-14Z with IFR CIGs and MVFR to occasional IFR VSBYs. Lull in activity between shortwaves will allow conditions to improve to VFR or high end MVFR during the day, then another period of showers and scattered tstms expected late afternoon into early evening with mainly MVFR conditions. A few storms could be strong to severe near KEWN and KOAJ. Developing post-frontal rain will lead to IFR CIGs 03Z-06Z.

Wednesday through Friday As of 415 PM Mon, Expect widespread showers and sub VFR conditions as a low pressure system produce widespread precipitation across the area late Tue night into Wed. Wednesday night as the low lifts NE, there is a chance for a mix of rain/snow to effect PGV and ISO. Vfr conditions will return Thursday and Fri as high pressure begins to build into the area.


Through Tuesday As of 925 PM Monday, No changes with increasing SE winds that will become more S late as warm front lifts N. The increasing winds will lead to seas building to 6 ft late tonight or early Tue central and srn wtrs.

Prev disc, SE winds are mainly 15 kt or less late today but will become S and increase to 10 to 20 kt with higher gusts tonight as a warm front moves north of the waters late. Low pressure is forecast to develop along front near Albemarle Sound late tonight. Resulting increase in winds will cause seas over the southern and central waters to build to 4 to 7 ft late tonight into Tue. Winds Tue are expected to become SW 10 to 20 kt with gusts to 25 kt keeping seas elevated over the southern and central waters throughout the day.

Tuesday night through Friday As of 415 PM Mon, Small Craft conditions will last through most of the week as secondary and major low pressure system moves through the coastal waters Tue evening then slowly up the east coast Wed/Wed night. Winds will veer to SW then NW 15 to 25 kt late Tuesday and NW-N Tue night and Wed. Seas will build 4-6 ft Tuesday and reach as high as 9-10 feet over the central and northern waters Wednesday night. Seas will start to gradually subside Thursday, but remain above 6 ft into Fri over the central and northern waters.

Watches, Warnings, Advisories

Nc, none. Marine, small craft advisory until 4 pm EDT Friday for amz152-154. Small craft advisory from 6 am this morning to 5 pm EDT Thursday for amz156-158.

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