Area Forecast Discussion
Issued by NWS Wilmington, NC

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436 FXUS62 KILM 222328 AFDILM Area Forecast Discussion National Weather Service Wilmington NC 728 PM EDT Thu Mar 22 2018 .SYNOPSIS... High pressure will build in across the area through early Saturday. A quick moving system will move across the area late Saturday and Sunday. High pressure will build in from the northeast for much of next week before a warming trend begins late in the period. && .NEAR TERM /THROUGH FRIDAY/... As of 3 PM Thursday...Big question mark for the period will be low temps tonight and freezing potential. Weak cold advection starting to wind down this afternoon and not expecting any additional surges of cold air overnight. The surface ridge axis will remain west of the area tonight, which will keep winds from becoming calm across the area. However, sheltered locations and typical cold spots will more than likely experience calm winds from time to time. Deep dry air will be in place with forecast soundings dropping precipitable water to 0.20 inch overnight. The result is likely to be cold spots several degrees below freezing tomorrow morning. Confidence is low on freezing temperatures being widespread. Think some areas will get below freezing, especially in Bladen, Robeson, and Pender counties. Have decided to go for a Freeze Warning for these counties. Do not plan on any frost or freeze headlines for the remainder of the forecast area. Guidance (even blended/consensus models) and partial thickness schemes all suggest temps above freeze for the bulk of the forecast area. Cannot rule out isolated freezing temps in these areas but do not think large portions of any one county will drop below freezing. Do not expect a lot in the way of frost development given the very dry boundary layer. Deep northwest flow continues Fri as the 5h trough axis, moving off the coast tonight, shifts farther east. Elongated surface high slips south of the area later Fri, maintaining low level northwest flow. Northwest flow will prevent warm advection but does lend itself to downsloping. It will also help keep the region very dry and humidity values will again drop into the 20% range. Airmass modification some downslope component will allow for highs a bit warmer than today, but not significantly so. Highs will struggle to reach low 60s. && .SHORT TERM /FRIDAY NIGHT THROUGH 6 PM FRIDAY/... As of 3 PM THURSDAY...Weak frontal boundary draped just to our south Friday night with a weak bubble of high pressure nosing in from the north. Mid level flow will be a downsloping west- northwesterly. In between 850mb flow will be WNW but backing in direction, which will put the wind increasingly angled to isotherms and lead to isentropic upglide. Cloud cover will increase from the southwest to northeast. On Saturday as the isotherms start getting packed tight leading to frontogenesis aloft, strengthening the upglide. Light rain will break out, favoring northern zones. Vorticity streaks overhead Saturday night pushing the forcing off the coast as the elevated front weakens. Plenty of clouds will remain behind but rainfall rates will diminish considerably. && .LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/... As of 3 PM THURSDAY...The extended period will feature considerable amplitude at the mid levels with an omega blocking pattern across the conus for a few days. This will keep the period mostly dry with modifying temperatures. Initially however, a cold front will be settling south embedded within yet another deep trough across the northeast. Some isentropic lift may provide a few cool rain showers Sunday but that`s about if for the period regarding pops. The entrenched surface high will take some time to modify and this is reflected in the temperature forecast/grids. HIghs will be stuck in the 50s Sunday and Monday warming to the 70s by Thursday which is much closer to normal. Overnight lows will follow the same trend with middle to upper 30s MOnday and Tuesday morning warming to the 50s by the end of the period. && .AVIATION /00Z FRIDAY THROUGH TUESDAY/...
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As of 00Z...High confidence of VFR tonight. No fog expected as dewpoints will remain in the 20s with a light northwest wind. VFR tomorrow. Winds begin to increase after 14Z as the inversion breaks. Late morning into the afternoon a few gusts to 15-19 kt with sct clouds at 6k expected. Extended outlook...VFR Fri/Sat. MVFR/IFR/Rain developing Saturday night and persisting into Sunday. VFR Mon/Tue.
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&& .MARINE... NEAR TERM /THROUGH FRIDAY/... As of 3 PM Thursday...Gradient continues to weaken and offshore flow has been slowly but steadily dropping through the afternoon. Small Craft Exercise Caution headline expires at 1500 and will not need to be extended. Offshore flow will remain in the 15 to 20 kt range this afternoon and overnight before dropping under 15 kt tomorrow. Surface high slowly shifts east-southeast on Fri, maintaining offshore flow. Seas currently running 3 to 5 ft will continue their slow downward trend this evening and overnight, dropping to 2 to 4 ft by Fri morning and 2 to 3 ft by midday Fri. SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/... As of 3 PM THURSDAY...Northerly winds Friday night as high pressure noses in behind a backdoor cold front stalled nearby to the south. As the high weakens flow will turn more onshore. The position of the boundary is not well agreed upon by various models so there is some forecast uncertainty with respect to winds. Prefer the more southerly solutions at this time due to mid level confluence to our north favoring the high not washing out completely. Low pressure developing on the front offshore could ramp winds up into Advisory levels late. LONG TERM /SUNDAY THROUGH TUESDAY/... As of 3 PM THURSDAY...Surface high pressure anchored well to the northeast will be the primary player for the extended marine forecast. With a blocking pattern at the mid levels this feature will remain in place through most of the period weakening late. Winds from the northeast of 20-25 knots will be in place most of Sunday dropping off only a couple of knots Monday. By later Tuesday winds diminish considerably. The prolonged higher winds will produce significant seas of 3-7 feet and a small craft advisory is a good bet based on both winds and seas for a good chunk of the period. && .ILM WATCHES/WARNINGS/ADVISORIES...
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SC...Freeze Warning from 5 AM to 9 AM EDT Friday for SCZ017-023-024- 032-033-039-055-058-059. NC...Freeze Warning from 5 AM to 9 AM EDT Friday for NCZ087-096-099- 105-107-109. MARINE...None.
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&& $$ SYNOPSIS...SHK NEAR TERM...III SHORT TERM...MBB LONG TERM...SHK AVIATION...MRR is the U.S. government's official web portal to all federal, state and local government web resources and services.