Area Forecast Discussion
Issued by NWS Wilmington, NC
Issued by NWS Wilmington, NC
Versions:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
839 FXUS62 KILM 131031 AFDILM Area Forecast Discussion National Weather Service Wilmington NC 631 AM EDT Mon May 13 2024 .SYNOPSIS... High pressure will move offshore today, allowing Gulf moisture to spread northward. Widespread showers should develop late tonight, joined by thunderstorms and heavy rain on Tuesday as a wave of low pressure approaches. Scattered showers and storms could continue through Wednesday, but dry weather is expected Thursday as high pressure builds in. More rain chances could develop Friday as the next storm system approaches. && .NEAR TERM /THROUGH TONIGHT/... A very broad storm system to the southwest will begin to impact the area today and tonight. For today expect only some cloud cover which could be quite variable at times. Still expecting highs to check in around 80 degrees or so. Pops enter the equation tonight via what appears to be very weak forcing focused inland. Some instability warrants the continued inclusion of thunder as well. && .SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/... A pair of shortwave troughs to our west and a 500 mb ridge just off the Southeast coast will lift a deep stream of Gulf moisture northeastward across the Carolinas Tuesday. Precipitable water values should rise to 1.7 inches - not record values for mid May but still in excess of the climatological 90th percentile. Isentropic lift embedded within a broad zone of warm advection should lead to widespread clouds and showers and forecast PoPs remain near 100 percent for Tuesday. The period of heaviest rainfall rates should reach northeastern South Carolina by late morning, spreading across southeastern North Carolina early Tuesday afternoon. Despite limited insolation due to thick clouds, unstable conditions should develop Tuesday through advection of warm, humid air at or just above the surface. GFS forecast soundings suggest up to 500-1000 J/kg of CAPE could develop. Bulk shear across the 0-6 km layer of 30-40 knots is sufficient to support organized storms, and curvature in low level wind profiles suggests enough helicity may be present to create a "non-zero" tornado potential. HREF updraft helicity ensembles suggest this threat may be highest Tuesday morning south of Florence and Conway. The more widespread threat could be locally heavy rainfall as up to three inches is forecast (storm total) in the Georgetown area. Mid level winds will veer more westerly late Tuesday afternoon/early Tuesday evening as the first of two upper impulses moves overhead. This will cause us to lose our moisture connection to the Gulf and rain chances are expected to decrease through the night. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... The second upper impulse should slow down and crawl northeastward across Kentucky and then the Mid Atlantic states Wednesday and Wednesday night, finally exiting the coast early Thursday. Enough sunshine should develop Wednesday to steepen lapse rates and generate CAPE of 1500-2000 J/kg. Enhanced westerly flow south of the upper disturbance will increase shear values enough that we`ll need to watch for a series of fast- moving convective clusters during the afternoon hours that could lay down strong, gusty winds. Forecast PoPs remain 50 percent or higher for all but Williamsburg and Georgetown counties. Convective activity should quickly wane with loss of heating Wednesday evening. High pressure should build southward across the area Thursday and Thursday night with dry weather expected. Models differ on the shape of the upper system approaching late in the week, but the next shortwave trough moving into the eastern half of the country should pull Gulf moisture northward again by Friday afternoon with scattered showers or storms again becoming possible. This system should move offshore by Saturday, but uncertainty increases rapidly for Saturday night into Sunday. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... VFR conditions for the most part through late tonight outside of the BR in CRE and ILM which should be short lived. Plenty of deep moisture moving in by Tuesday morning. Some guidance has IFR now developing inland and although I wouldn`t be surprised by brief IFR...prevailing MVFR seems a bit more reasonable at this point. No doubt this will be the beginning of a couple of challenging days for the aviation community around here. Extended Outlook...Flight restrictions may occur Monday night into Tuesday with the next weather system moving in. Improving conditions into Thursday. Another system approaches the area for next weekend. && .MARINE... Through Tonight...After several quiet days the coastal waters will see increased winds and eventually seas via an extensive storm system to the south west. Light winds from the southeast will increase to the higher end of a 10-15 knot range by Tuesday morning. Significant seas will see an increase as well from the current two feet to a healthy range of 2-4 feet. Tuesday through Friday...Mariners are in for difficult weather conditions at times this week. Moderate to strong south winds are expected to develop Tuesday as a warm front lifts north across the area. Widespread showers and a few thunderstorms with heavy rain are expected during the day. Winds and seas will likely reach Small Craft Advisory thresholds. Showers may continue through Tuesday night as a wave of low pressure moves northeastward across the Coastal Plain just inland from the beaches. A cold front following behind the area of low pressure should push offshore Wednesday, however unsettled weather conditions including shifting wind directions and periods of showers and thunderstorms may linger into Wednesday evening before high pressure finally builds across the Carolinas Thursday into Friday. && .ILM WATCHES/WARNINGS/ADVISORIES... NC...None. SC...None. MARINE...Small Craft Advisory from 11 AM Tuesday to 9 AM EDT Wednesday for AMZ250-252. && $$ SYNOPSIS...TRA NEAR TERM...SHK SHORT TERM...TRA LONG TERM...TRA AVIATION...SHK MARINE...TRA/SHK