Area Forecast Discussion
Issued by NWS Newport/Morehead, NC

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000 FXUS62 KMHX 141135 AFDMHX Area Forecast Discussion National Weather Service Newport/Morehead City NC 635 AM EST Fri Dec 14 2018 .SYNOPSIS... A strong storm system will affect the area today into the weekend. High pressure will gradually build in from the west early through mid next week. Another storm system may impact the area late next week. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... As of 635 AM Thursday...A cut off upper low is forecast to slowly track from the Gulf coast today, to Alabama tonight, then East TN Sat. At the surface, a coastal warm front will move inland today and tonight as high pressure moves out into the Atlantic. As this boundary moves across the area, an area of low pressure will move northeast along it across the coastal plain of NC tonight. Moisture will advect into the area from the Gulf of Mexico and the Gulfstream with PW values increasing to around 1.75" by early evening which is near the climatological maximum for mid-December. Warm advection will be increasing ahead of the advancing upper low and combined with increasing upper level divergence ahead of the upper low will produce strong lift across eastern NC beginning this afternoon. This will eventually lead to the development of widespread rain showers across most of the area this afternoon. Dry air currently over the area will initially limit rainfall intensity through early afternoon, with heavier rains then expected to develop by evening especially across the western portion of the region. With the dry air persisting longer along the Outer Banks, we are expecting less in the way of precipitation today and there will be a large gradient in PoPs/QPF with highest over the western half of the region. Temperatures are forecast to slowly rise today with daytime highs expected late as southerly flow develops and strengthens. Highs will range from the upper 50s across the northern coastal plain to the mid 60s coast. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/... As of 635 AM Friday...Very active weather is expected across Eastern NC tonight and Saturday. Extreme values of PW for this time of year combined with strong ascent and confluent low level flow will lead to widespread heavy showers and possible strong to severe thunderstorms, especially along the coast where instability is forecast to be greatest. Rainfall amounts of 2-3 inches, with locally heavier mounts will be possible by Sat evening. Thus will continue current Flash Flood Watch for the entire area due the expected heavy rains and already saturated soils. In addition, the strong kinematic environment with increasing wind fields will produce 0-6km bulk shear around 40- 50 kt, however instability will be lacking with MUCAPEs forecast AOB 500 J/kg. Damaging wind gusts and isolated tornadoes are threats in this high shear/low CAPE environment tonight into early Sat afternoon. The precipitation is forecast to taper off from west to east late Sat. With increasing southerly flow temps will likely continue to rise tonight with the 24 hr max temps occurring overnight. Temps may level off late tonight then increase diurnally Sat. Readings will be well into the 60s during this time with some guidance suggesting temps possibly rising into the 70s Sat. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... As of 330 AM Friday...An upper low will track just north of the area through Sunday with additional isolated to scattered showers possible. High pressure builds in from early to the middle of next week. Another storm system is expected to approach the area late next week. Saturday night through Sunday night...The upper cut-off low will track from the southern Appalachians to just north of the area this period with additional cyclogenesis occurring just off the mid-Atlantic coast ahead of the trough. Deeper moisture expected to slide offshore by Saturday evening with PW values dropping to less than an inch but could see isolated to scattered showers across the area this period with steep mid- level lapse rates invof the upper low and vort maxes that may rotate through the upper low as depicted in some models. The 00z ECMWF has come into agreement with other models tracking the low just north of the area, lifting from the Piedmont across SE VA Sunday. Have chance PoPs area wide Saturday evening, but gradually taper PoPs down through the rest of the period. Temps will be cooler Saturday night than the previous night but still around 10-15 degrees above normal from around 50 inland to lower 50s coast. Temps cool to just above climo Sunday and Sunday night with highs in the mid 50s to around 60 and lows in the low to mid 40s. Monday through Wednesday...A strong northern stream jet digging into the Great Lakes and Northeast will allow the upper low to quickly lift NE away from the area early next week with surface high pressure building into the region from the west bringing dry conditions for the first half of the work week. Temps will continue around or a little cooler than climo with highs generally in the 50s and lows in the 30s. Thursday...The next storm system is progged to approach the area for the latter half of next week, however there remains substantial spread in the models at this time whether northern stream energy digging across the Northern Plains into the Midwest will phase with a mid-level trough/low pressure over the Southern Plains to develop a longwave trough across the eastern CONUS. This solution will bring a strong Gulf moisture feed into the area potentially bringing another round of heavy rainfall across the area as shown in the 00z operational ECMWF and CMC. If phasing doesn`t occur and the northern stream dominates, the Gulf moisture tap will be cut off and would likely see a dry frontal passage late in the week as depicted by the operational GFS. Due to the uncertainty have followed WPC guidance closely late next week. && .AVIATION /12Z FRIDAY THROUGH TUESDAY/... Short Term /through Tonight/... As of 635 AM Friday...VFR conditions should continue into the afternoon, then cloud bases and visibilities will lower and should drop to MVFR levels by late afternoon as showers become widespread across the region. IFR conditions will then be likely tonight in moderate to heavy rain showers. Long Term /Saturday through Tuesday/... As of 4 AM Friday...A strong low pressure system will slowly move across the region through the weekend bringing periods of sub-VFR conditions. The heaviest rain/lowest cigs/vsbys expected though Saturday morning. Conditions begin to improve late Saturday but additional showers will be possible Saturday night and Sunday with periods of sub-VFR conditions possible at times. High pressure builds in from the west early next week with pred VFR conditions expected. && .MARINE... Short term /through Saturday/... As of 635 AM Friday...No changes to previous forecast thinking. SCA`s continue in effect for the near shore waters and Pamlico Sound as marine conditions are forecast to slowly deteriorate this afternoon and tonight as a complex storm system moves into NC. Winds are currently light north of Bogue Inlet and mainly from the E early this morning with seas running 2-4 feet in long period (10-13 second) swells. Expect increasing winds and building seas through the day today. E/SE winds 10-20 kt increasing to 15-25 kt during the afternoon and evening then becoming S late tonight 20-25 kt late tonight and early Sat. Seas are forecast to build to 5-8 ft south of Oregon Inlet and 3-5 ft north. Tonight into early Sat seas build further to 7-11 ft. Sat afternoon winds are forecast to become SW 15-20 kt with seas slightly subsiding to 5-8 ft late. Long Term /Saturday night through Tuesday/... As of 415 AM Friday...SW winds around 5-15 kt Saturday night will slowly veer to W around 10-20 kt Sunday, the NW Sunday night. Could see winds as high as 20-25 kt across the northern coastal waters Sunday night as low pressure develops off the mid-Atlantic coast. Gradients remain tight into early next week with a surface trough progged to push across the waters Monday night. Winds back to west around 10-15 kt Monday, then become NW around 15-25 kt Monday night after the passage of the trough, then winds gradually diminish through the day Tuesday. Seas around 5-9 ft Saturday evening gradually subsides to 3-6 ft by late Sunday and 3-5 ft Monday but build back to 4-6 ft across the northern/central waters Monday night and Tuesday with the secondary surge. && .HYDROLOGY... As of 330 AM Friday...Flash Flood Watch will continue for all of Eastern NC with heavy rainfall amounts of 2-3 inches expected to fall during the upcoming storm system fro late today into Saturday. The highest rainfall totals are expected along the coast where some isolated amounts of 4 + inches are possible. The heaviest precip will fall overnight into Saturday, and given the very saturated ground, there will likely be flooding of poor drainage areas, and the potential for localized flash flooding. Local streams and rivers are already running near or above flood stage, and the expected rainfall will lead to additional river flooding across Eastern NC. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...Flash Flood Watch from 1 PM EST this afternoon through Saturday afternoon for NCZ044-079-090>095-098. Flash Flood Watch from 4 PM EST this afternoon through Saturday afternoon for NCZ029-045>047-080-081-103-104. MARINE...Small Craft Advisory from 7 PM this evening to 10 AM EST Saturday for AMZ135. Small Craft Advisory from 7 PM this evening to 9 AM EST Monday for AMZ150. Small Craft Advisory from 2 PM this afternoon to 5 PM EST Monday for AMZ152-154. Small Craft Advisory from 11 AM this morning to midnight EST Sunday night for AMZ156-158. && $$ SYNOPSIS...MHX NEAR TERM...JME SHORT TERM...JME LONG TERM...SK/SGK AVIATION...JME/SK MARINE...JME/SK HYDROLOGY...MHX is the U.S. government's official web portal to all federal, state and local government web resources and services.