Sunrise 6:11 AM   Sunset 8:11 PM Moonrise 7:50 AM   Moonset 11:25 PM

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FXUS62 KRAH 111932 AFDRAH

Area Forecast Discussion National Weather Service Raleigh NC 330 PM EDT Sat May 11 2024

SYNOPSIS
A surface trough and upper level disturbance will move across the Mid Atlantic region this evening. High pressure will build across the Southeast and Mid Atlantic region on Sunday, then shift off the Southeast coast Monday. A storm system will move in from the west Monday night through Wednesday, bringing periods of rainy weather.

NEAR TERM /THROUGH SUNDAY NIGHT/
As of 330 PM Saturday...

Through tonight: Still expect a brief window of isolated to scattered showers this evening, mainly across the Piedmont and N Coastal Plain. The potent mid-upper low now over S Lk Huron has a trailing shortwave trough don through E OH into KY. The upper jet streak diving into the trough base from IN continues to generate strong forcing for ascent to the east of the low, contributing to a band of showers with embedded isolated stronger convection from SE Ontario through PA/WV. Sufficient recovery has occurred west of this band within 1000 J/kg SBCAPE amidst 7+ C/km mid level lapse rates and 8-9 C/km low level lapse rates to contribute to a secondary band of strong to severe convection in E OH. We shouldn't see these kinds of steep lapse rates by the time the shortwave trough shifts E into and through the Mid Atlantic region, as nocturnal stabilization will be starting by then with CINH developing, but we are likely to see the tail end of the shower band, now over WV into E KY swinging through our area this evening, just ahead of the mid level trough axis. The scattered to occasionally broken high-base convective cu now over central NC (esp E half) will dissipate a bit toward sunset, then clouds will quickly increase anew from the NW as the pre-trough moisture plume spreads in. The best chance of showers should be 22z- 03z in the NW trending to 01z-06z further SE, although our far SE sections are likely to stay dry as the trough dampens upon approach with our SE farthest removed from the forcing for ascent and potential weak elevated CAPE. Any one location should see little more than a few hundredths falling over an hour or less, and we could see a few gusts ahead of and with these showers. Skies will then clear out NW-SE behind the showers. Expect lows in the upper 40s to mid 50s.

Sunday/Sunday night: With overall very low PW moving in as surface high pressure builds overhead, quiet and dry conditions are likely, with little more than a period of scattered to broken high-base flat cu in the afternoon and increasing high clouds from the NW late Sun night within predominant NW steering flow. Low level thicknesses will have recovered a bit from this morning but will still be 15 to perhaps 20 m below normal, and this balanced with decent insolation favors highs in the mid 70s to around 80, near to slightly below normal. Lows in the mid 40s to mid 50s Sun night with good radiational cooling conditions expected. -GIH

SHORT TERM /MONDAY THROUGH MONDAY NIGHT/
As of 120 PM Saturday...

A shortwave trough presently located near the Four Corners region is forecast in most of the guidance to reach central/eastern MO by Tue morning. Before that happens, we will see shortwave ridging most of Mon. Some subtle waves of energy will stream in during the day but would only lead to some increased mid/high clouds. Warm advection in return southerly flow from a high shifting offshore should allow highs rise near or a few degrees above normal in the upper 70s to low 80s. As the aforementioned trough shifts into the MS Valley overnight into Tue, low-level WAA and moisture transport will increase from the southwest as a warm front lifts north into the SE US. Precipitable water will increase some 150-percent of normal to 1.4-1.5 inches as isentropic ascent increases. Most guidance holds off on showers toward the late-evening and overnight period, spreading across the west/southern Piedmont earliest. Have kept high chance to likely showers overnight into Tue morning as a result.
Showers may not reach the Coastal Plain until sunrise Tue. Lows are forecast in the upper 50s to low 60s.

LONG TERM /TUESDAY THROUGH SATURDAY/
As of 247 PM Saturday...

Tuesday/Wednesday: There is good consensus amongst models supporting an upper trough lifting through the TN Valley and into the southeast Tuesday into Wednesday. This feature will support increasing swly flow aloft and deep moisture advection into the southeast with PWAT rising 150 to 175 % of normal.

At the sfc, a series of lows are forecast to develop: one over the IN/IL/TN/AK vicinity, and then perhaps another one somewhere over the Carolinas. There is some uncertainty wrt to the latter low and where it develops/evolves with varying solutions. However, in general, these features, along with upper support associated with the trough should combine to produce a series of wet day for central NC Tuesday and Wednesday.

Guidance suggests some instability will likely develop Tuesday afternoon, but the better combination of shear/instability appears to mostly be to our south at this point. However, if the low traverses a bit more west through our Piedmont, would not be surprised if locations south and east of Raleigh tap into a bit better instability/shear which could promote the potential for some stronger storms. However, there's a bit too much uncertainty this far out and thus we'll continue to monitor.

Additional showers and a few storms will remain possible on Wednesday as a cold front moves into the area with highest chances in the afternoon/early evening. Ensemble guidance currently maintains a bit better shear along the coast on Wednesday, but again would not be surprised if some of this better shear trickles into our far southeast zones Wednesday afternoon.

Temperatures on Tuesday will largely depend on where the southeast low tracks, but for now leaned on a bit warmer guidance with low to mid 70s for highs. Temps should rise a bit more on Wednesday, reaching the upper 70s/lower 80s.

Thursday through Saturday: Ensemble guidance is pretty consistent in moving the upper trough and associated anomalous moisture offshore by 12Z Thursday (although the deterministic EURO lags behind an upper low over the Chesapeake through late Thursday). Brief upper ridging follows, which should promote dry conditions Thursday. Temps on Thursday will remain warm in the upper 70s/lower 80s.

The ridge quickly breaks down as another upper trough lifts into the TN valley Friday into Saturday. Increasing moisture transport and upper forcing will promote additional showers/thunderstorm chances Friday into the weekend. Temperatures in this time range will remain in the upper 70s/lower 80s.

AVIATION /18Z SATURDAY THROUGH THURSDAY/
As of 1245 PM Saturday...

Dry weather and VFR conditions will dominate across central NC through Sun, although passage of a strong upper level disturbance through the Mid Atlantic region this evening into the early overnight hours will bring a band of showers across the area from NW to SE, mainly affecting the northern terminals. But cloud bases are expected to remain largely VFR even within showers, with a low chance of brief MVFR cigs/vsbys. Surface winds may briefly be gusty and erratic in and near these showers. Any clouds will clear out late tonight, leaving fair skies through Sun.

Looking beyond 18z Sun, VFR conditions and dry weather are expected through at least Mon. Rain and isolated storms, with a high chance of sub-VFR conditions and increasing winds aloft, are expected to overspread the area starting Mon night, with sub-VFR conditions lasting through Wed morning, although shower chances will persist through Wed. Dry VFR conditions should return for Thu. -GIH

RAH WATCHES/WARNINGS/ADVISORIES
None.

Bannermans Branch
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Sat -- 12:55 AM EDT     0.03 feet Low Tide
Sat -- 06:11 AM EDT     Sunrise
Sat -- 06:29 AM EDT     1.55 feet High Tide
Sat -- 08:49 AM EDT     Moonrise
Sat -- 01:53 PM EDT     0.08 feet Low Tide
Sat -- 07:03 PM EDT     1.22 feet High Tide
Sat -- 08:04 PM EDT     Sunset
Tide / Current data from XTide NOT FOR NAVIGATION

Bannermans Branch, Northeast River, North Carolina, Tide feet

Castle Hayne
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Sat -- 03:15 AM EDT     2.03 feet High Tide
Sat -- 06:12 AM EDT     Sunrise
Sat -- 08:50 AM EDT     Moonrise
Sat -- 10:39 AM EDT     0.11 feet Low Tide
Sat -- 03:49 PM EDT     1.59 feet High Tide
Sat -- 08:04 PM EDT     Sunset
Sat -- 10:27 PM EDT     0.11 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION

Castle Hayne, Northeast River, North Carolina, Tide feet

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