Area Forecast Discussion
Issued by NWS Newport/Morehead, NC
Issued by NWS Newport/Morehead, 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
976 FXUS62 KMHX 121954 AFDMHX Area Forecast Discussion National Weather Service Newport/Morehead City NC 354 PM EDT Mon Aug 12 2024 .SYNOPSIS... Cold front pushes offshore tonight while high pressure builds in from the north. High pressure will then remain over the Eastern Seaboard into this weekend. && .NEAR TERM /THROUGH TONIGHT/... As of 345 PM Monday... - Heavy rain/flooding risk continues through early this evening - Flood Watch in effect until 10pm tonight - Overnight fog potential Early this afternoon, an area of low pressure was analyzed near Columbia, SC. A stationary frontal boundary extends from central SC east out into the SW Atlantic. North of the SFC boundary, there appears to be an elevated (925-850mb) front from Charlotte east through around Morehead City. It`s this boundary, plus a modest upper level shortwave aloft, that will be the focus for showers and thunderstorms through this evening. Based on radar and satellite trends, it appears the greatest risk of deeper convection will be focused along and south of HWY 264. The previous shift nicely outlined this area with the Flood Watch, and this continues to look solid. Regarding the heavy rain threat, the 12z MHX sounding had a PWAT over 2", and this should be representative of much of ENC. The high PWAT airmass plus moderate instability (MUCAPE > 2000 j/kg) should be more than supportive of higher rainfall rates. 1-hr flash flood guidance is around 2-3", and like yesterday, I expect the deepest convection to be capable of 2-3"/hr rainfall rates, which will support a flash flood risk. Additional rainfall will only add to the ongoing river flooding as well. Regarding the severe weather potential, the combination of MLCAPE of 1000-2000 j/kg and 25-40kt of deep layer shear appears supportive of at least some risk. I expect the main hazard today to be heavy rain and flooding, but if any stronger cores can develop, there would be an accompanying risk of severe weather (mainly a wind and hail threat). In the wake of this afternoon`s shortwave, subsidence and drying aloft should lead to a decreasing chance of thunderstorms from north to south. If sufficient clearing occurs overnight, there will be an increased risk of fog development. A period of dense fog cannot be ruled out, especially across the coastal plain. && .SHORT TERM /TUESDAY/... As of 1245 PM Monday... - Scattered afternoon thunderstorms possible Any areas of fog should mix out by mid-morning, with several hours of dry conditions expected through early afternoon. By mid to late- afternoon, another shortwave aloft combined with lee troughing at the SFC should support isolated to scattered thunderstorms. I expect the primary focus to be upstream across central NC, but storms may have a tendency to move east into the coastal plain of ENC thanks to increasing flow aloft. Instability is forecast to be weaker on Tuesday compared to today, but deep layer shear will be stronger, so there`s at least some support for a stronger storm, or two. && .LONG TERM /TUESDAY NIGHT THROUGH MONDAY/... As of 5 AM Monday...A drying trend will commence mid-week as a cold front offshore slowly sags southward and high pressure builds into the area from the NW. However, upper trough remains centered over the eastern CONUS with a series of shortwave trough pushing across the area that will aid in initiating isolated to scattered showers and thunderstorms at times. Greatest chances will be during the afternoon/evening hours when instability is maximized. PWATs lower to below 1.25" on Wednesday so storms will not be the prolific rain makes that we have been experiencing over the past week. Temps will actually be a couple of degrees below normal with highs in the mid 80s and it won`t be quite as oppressive humidity with dew point temps in the mid to upper 60s. The upper trough pushes off the East Coast Thursday and Friday with upper ridging building in from the west. We will be closely watching the current PTC #5, likely to become Ernesto later today, as it pushes across the Caribbean Island through the week. Current NHC forecast is for it to lift north of the Greater Antilles as it interacts with the departing upper trough and track well east of the area late in the week. While we are not expecting direct impacts from this system at this time, large swells are expected to impact the beaches bringing an increased rip current risk and large surf beginning Friday and continuing through the weekend. Locally, high pressure will continue to dominate across the area and we will finally get a couple of days to dry out. Temps will continue slightly below normal with highs in the mid 80s and dew point temps in the mid 60s. An upper low moves into the Great Lakes Friday into the weekend with an upper trough digging back into the East Coast and a cold front slowly advancing toward the area bringing increasing chances for showers and thunderstorms across the region Saturday and Sunday. Seasonable temps continue with highs generally in the mid 80s. && .AVIATION /20Z MONDAY THROUGH SATURDAY/... SHORT TERM /Through 18z Tuesday/... As of 1245 PM Monday... - TSRA likely (60-80% chance) through early this evening - BR/FG/sub-IFR potential overnight SCT to numerous TSRA will impact much of ENC through early this evening, with periods of IFR, or lower, conditions, especially in VIS. Lower CIGs will accompany the TSRA as well. The strongest TSRA will be capable of gusty/erratic winds and hail. The TSRA risk should decrease from north to south tonight as slightly drier air works in aloft, and as lift decreases. If sufficient breaks in the clouds occur, there will be a risk of BR/FG and sub-IFR conditions. A period of LIFR VIS is possible (20-40% chance) if FG develops. BR/FG should mix out by mid- morning Tuesday, with a lower TSRA risk through early Tuesday afternoon. LONG TERM /Tuesday night through Saturday/... As of 530 AM Monday...Chances for sub-VFR conditions will gradually diminish through the week as high pressure builds in and we finally begin to dry out. Isolated to scattered showers and thunderstorms chances continue into Wednesday that could bring brief sub-VFR conditions with dry weather expected Thursday and Friday. Light winds and good radiational cooling conditions will continue to bring the chance for late night/early morning fog and stratus most morning, especially giving the saturated ground. && .MARINE... SHORT TERM /through Tuesday/... As of 215 PM Monday... - Thunderstorm risk continues into this evening - Improving boating conditions by Tuesday An upper level wave moving through will support scattered to numerous thunderstorms across area waters through this evening, with a decreasing risk tonight into Tuesday. Outside of the thunderstorms, the area will be in a northeasterly flow of 5-15kt. The wind will be high enough to support 3-4 ft seas through Tuesday, but all things considered, conditions will be improving compared to the past several days. LONG TERM /Tuesday night through Saturday/... As of 6 AM Monday...Good boating conditions through much of the week with high pressure building into the area bringing NE winds around 5-15 kt through Friday. Wind finally begin to veer to E and SE late Friday into Saturday as the high moves offshore. Seas will generally be around 2 to 3 ft through early Friday but then we will begin to see long period swells from soon to be Ernesto begin to move into the waters late Friday which will build through the weekend. && .HYDROLOGY... As of 345 PM Monday...Scattered to numerous showers and thunderstorms will continue to impact ENC along and south of HWY 264 through early this evening. Flash Flood guidance is around 2-3" in one hour, and this should easily be reached with the strongest thunderstorms, and will be supportive of a few instances of flash flooding. The Flood Watch will continue as-is for now, but we may be able to trim the northern edge of the watch as thunderstorms move out of that area. River flooding will continue across many river basins including the Trent, Neuse, New and Tar Rivers as well as several tributaries to the rivers through the weekend and into next week with abundant rain falling will upstream of the FA. It should be noted that some of the worst river flooding is still yet to come, with some rivers not cresting until late this week or this weekend. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...Flood Watch until 10 PM EDT this evening for NCZ044-079>081- 090>092-094-193>196-198-199. MARINE...None. && $$ SYNOPSIS...MHX NEAR TERM...RM SHORT TERM...RM LONG TERM...SK AVIATION...RM/SK MARINE...RM/SK HYDROLOGY...MHX