Area Forecast Discussion
Issued by NWS Wilmington, NC

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094 FXUS62 KILM 281739 AFDILM Area Forecast Discussion National Weather Service Wilmington NC 139 PM EDT Wed Sep 28 2016 .SYNOPSIS... A cold front approaching from the west will stall through mid- week before moving across the area Thursday into Friday. Dry high pressure will build into the area by the weekend. && .NEAR TERM /THROUGH TONIGHT/... As of 1000 AM Wednesday...Anomalously strong upper low centered near Lake Michigan will deepen and sink slowly SE through tonight. Beneath this feature, a stationary front will meander across western/northern NC and into VA, keeping the local area firmly within the warm sector today. While this will create temperatures well into the 80s this aftn, about 5-8 degrees above normal for late September, it will also allow humidity to increase and create an environment ripe for convection. SPC has placed the i-95 counties in a MRGL risk for today, and while total storm coverage is not expected to be widespread, any individual storms will have the potential to produce a strong wind gust. The combination of warm temperatures and high humidity will drive SBCape to 2500 J/kg, which will combine with subtle height falls, PWATS to 1.5 inches, and 20-25 kts of 0- 6 km shear to produce that aforementioned isolated strong wind threat. Highest POP will be featured along and west of i-95, which is agreed upon by both the HRRR and NSSL 4km WRF, and makes sense as it is closest to the upper low and along a moisture gradient. Heavy rain will also be possible in stronger storms, but motion should be great enough to prevent any significant flooding unless several storms pass across the same area. This evening and tonight, a shortwave will move out of the gulf along the periphery of the upper low and overhead the CWA. This will likely bring the best chance for showers with isolated tstms to the eastern portion of the CWA, but no severe is expected tonight. Mins will remain above normal for the time of year, dropping only to around 70. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... As of 345 AM Wednesday...Of the 2 days, Thu will be the wetter of the 2 and exhibit the higher POPs. The main feature will be the cutoff low making its furthest southern positioning across the Central Appalachians. Thursday will feature embedded and stronger mid-level s/w trofs rotating around this cutoff low. The one Thu morning moves NE of the FA with the eastern 1/3 to 1/2 seeing ongoing convection at the start of the day, moving out of the FA by late morning. The next s/w rotating around and closer to the cutoff low, will help push a dry slot across portions of the FA late Thu aftn and night. With it not entirely thru the FA, will keep a POP for the far eastern portions of the ILM CWA Thu night into Fri. Finally, the models indicate the dry slot will finally shunt the remaining moist air off the Carolina coasts by late Friday. Improving wx conditions across the FA during Fri into Fri night. Max/Min Temps, stayed closer to a consensus with a lean toward the MET mos guidance based on its decent performance the past couple days. && .LONG TERM /SATURDAY THROUGH TUESDAY/... As of 3 AM Tuesday...Despite the fact that the long term begins with an impressively large cutoff to our west the weather will be pretty quiet. The reason for this is that we will be in the dry slot of the occluded surface low to our NW and the deep moisture will be off the coast. Sunday and Monday as the weakening front pushes through some of this moisture may get drawn back to the coast for some minor rain chances-all while temperatures remain close to their seasonable norms. The front washes out by Monday leaving behind a weak surface pattern while mid level heights build. There will still be no real forcing for precipitation and no low level thermal advection to change temperatures much from the values earlier in the period. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... As of 18Z...VFR conditions this afternoon and evening outside of SCT 3SM TSRA BKN030CB across inland terminals KLBT/KFLO BTWN 22-02z. Isolated showers throughout region aft 02z as disturbance aloft moves north over interior zones and ocean showers move onshore at coastal terminals overnight into very early Thursday. VFR Thursday 13z-18z as drier air spreads into the region with SKC for most locations, TCU at end of TAF cycle. EXTENDED OUTLOOK...Primarily VFR. Isolated to scattered afternoon showers through much the period, although limited in strength and coverage due to dry air aloft. && .MARINE... NEAR TERM /THROUGH TONIGHT/... As of 1000 AM Wednesday...Stalled front will remain NW of the waters today, with a weak pressure gradient persisting. Winds currently around 5 kts will become SE at 5-10 kts, and may increase further to 10-15 kts late tonight with continued veering to the SW. This will create seas of 2-3 ft through the near term, with a Southerly wind wave and low amplitude SE swell comprising the spectrum. Showers with isolated tstms will be possible across the waters late tonight as well. SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... As of 345 AM Wednesday...Sfc pressure pattern and a tightening- some of the gradient, will result in SW winds at 10 to around 15 kt thru this period. Significant seas will run 2 to 3 feet with 4 footers possible Wed and Thu when winds will be closer to 15 kt sustained due to the semi-tightened sfc pg. Wavewatch3 and local Swan keeps the ESE 11 second period ground swell affecting the local waters but with some degradation. Local wind driven waves at 4 to 6 seconds will become the more dominant feature of the significant seas by late Thu thru Friday. The sfc cold front will finally push to the Carolina coasts during Friday, and stalling just offshore the ILM Waters Friday night. The dry slot or tongue will push across the waters late Friday ending the threat for showers and thunderstorms. LONG TERM/SATURDAY THROUGH SUNDAY/... As of 3 AM Tuesday...A weakening cold front running parallel to the coast will only slightly shift through the period moving from just onshore to just offshore. It`s parent surface cyclone will be well occluded and thus deprived of its energy source and so the whole system will feature a baggy and poorly defined pressure pattern. This is good news for most mariners though as winds will be quite light and somewhat variable through the period. Seas will be slightly elevated above what such slack winds would otherwise support since spectral wave bulletins show a myriad of wave elements. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...None. NC...None. MARINE...None. && $$ NEAR TERM...JDW SHORT TERM...DCH LONG TERM...MBB AVIATION...Colby

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