####018008516#### FXUS62 KRAH 030625 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 225 AM EDT Fri May 3 2024 .SYNOPSIS... An upper level high pressure ridge extending over the area this morning will shift to our southeast later today. A surface backdoor front will drop into northeast North Carolina tonight then stall out, holding over North Carolina through Saturday before slowly washing out. A series of weak upper level disturbances will move through the region from late today through Sunday, bringing periods of unsettled weather. && .NEAR TERM /TODAY THROUGH TONIGHT/... As of 150 AM Friday... A last largely dry day before we start trending wetter, esp W. Very weak surface troughing sits over the W Piedmont of NC currently, capped by the mid-upper level ridge axis extending over the central and eastern Carolinas. PWs remain on the low side, under 1" except in our far S (where there is a risk for some stratus and fog for a few hours early this morning). With stable and dry mid levels, we'll again be dry today, albeit with increasing high then mid level clouds, along with a few high-based afternoon cu, as a mid level perturbation/remnant MCV currently over the Mid South shifts eastward into our area. Low level thicknesses will again be well above normal, with models showing values several meters higher than yesterday when we reached the upper 80s to lower 90s. The gradual increase and thickening of clouds will curb heating slightly, but we should still be able to reach the upper 80s to around 90, perhaps a few lower 90s east, close to but generally below record highs (see climate section below). As the steadily dampening wave shifts E of the Appalachians, clouds will continue to spread in tonight from the W, with PWs near or above 1.5" spreading into at least the Piedmont and Sandhills. CAPE is minimal and elevated, and the flattening wave and weak mid level flow will provide little in the way of dynamic forcing for ascent. but the deepening moisture and a couple hundred J/kg will be enough to support isolated to scattered showers and perhaps a storm overnight, in the Triad this evening then spreading into the rest of the Piedmont after midnight. In addition, models are in good agreement that the backdoor front now stretching across the Mid Atlantic region will continue to push southward into our area late tonight, bringing an area of stratus spreading in from the N and NE, and increasing low level mass convergence along this backdoor front may prompt additional light rain areas in its vicinity. Lows from around 60 the mid 60s. -GIH && .SHORT TERM /SATURDAY AND SATURDAY NIGHT/... As of 225 AM Friday... Confidence is high on increasing chances for showers and a few storms, although no one will see rain the entire day, and pinpointing the location and motion of what should be shower/storm clusters is challenging. PWs will continue to rise, with models indicating a swath of 1.5-1.75" values surging up through central NC, in the 90th percentile and even nearing daily records. This will occur in tandem with increasing low level moisture flux drawing Atlantic moisture into our area. As the backdoor front settles further into the area Sat morning, followed by a very gradual weakening and washing out, the considerable stratus over much of the area, esp N and W sections, will hinder heating and destabilization until it retreats and breaks up later in the day. And our large scale dynamic forcing for ascent will be poor, given the weak mid- upper level flow, but we may still feel the effects of MCVs emanating from today's Plains convection as it shifts into our area late Sat through Sat night. All of this supports scattered to numerous clusters of showers and storms, particularly in areas W of I-95 where moisture will be deepest, with the highest pops in the Triad and perhaps a secondary focus along the weakening backdoor frontal zone. The storm threat will be limited, given the weak deep layer bulk shear and modest CAPE, but a few storms will remain possible mainly in the afternoon and evening. Rain chances will persist overnight with further moistening of the low levels with confluent 925 mb southerly flow strengthening to 15-25 kts with both Atlantic and Gulf taps. While areally averaged rainfall amounts aren't likely to be high, given the anomalously high PW and somewhat slow storm motion with cell mergers possible, isolated areas could see local rainfall totals that could present minor urban flooding issues, esp in the Triad region, despite the recent dry weather. With mostly cloudy to cloudy skies, expect highs from the mid 70s N and W to lower-mid 80s SE. Lows in the 60s. -GIH && .LONG TERM /SUNDAY THROUGH THURSDAY/... As of 220 PM Thursday... The first half of the extended forecast will feature an unsettled pattern. A weak surface low will be over the Ohio River Valley Saturday morning, slowly move to the east over Virginia by Sunday morning, then dissipate. A cold front will extend to the south from the low, and the front will be the primary rain-maker over the weekend. Extended likely pops a bit farther to the east both Saturday and Sunday. Rainfall amounts will range from a quarter inch in the southeast to nearly an inch in the northwest - needed rainfall, but not enough to change the drought status (almost all of which is D0 - abnormally dry - in our area). All locations will have at least a slight chance of thunderstorms, although instability values will be a little higher in the west. After the upper 80s and lower 90s of today and tomorrow, highs will be more seasonable for the weekend, ranging from the upper 70s the mid 80s. An upper level trough will approach the area Monday and move overhead Tuesday, bringing a chance of showers and thunderstorms to all locations. The forecast should then generally dry out for the middle of the week. However, an upper ridge will build across the Carolinas, and with southwesterly surface flow, temperatures will rise above normal again. By Wednesday and Thursday, highs should be in the lower 90s with lows around 70, values more typical of July and August than early May. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... As of 1250 AM Friday... Except for a chance of MVFR vsbys/cigs in the SE including FAY 08z- 12z this morning, VFR conditions are likely to hold through at least this afternoon across all central NC terminals, but with gradually increasing high and mid clouds. Starting after 21z, an upper level disturbance along with daytime heating will prompt isolated to scattered showers and a few storms pushing into the west (INT/GSO), with these chances lasting through the overnight hours, however VFR conditions will still be dominant. However, starting after 04z tonight, a backdoor front dropping into far N and NE sections will bring a good chance for IFR cigs and MVFR to IFR vsbys into northern areas, along and behind the front. However, these adverse aviation conditions should hold N of the primary terminals until after the end of the TAF valid period at 06z Sat. Looking beyond 06z Sat, as the backdoor front settles southward well into central NC, sub-VFR cigs/vsbys are expected to spread south through most of the area 06z-12z Sat. As the front slowly lifts back north and washes out, conditions will slowly improve back to VFR Sat from SE to NW, with the Triad (INT/GSO) remaining sub-VFR well into the afternoon. But the chance for sub-VFR conditions within scattered to numerous showers and storms will be high, especially at INT/GSO/RDU, Sat through Mon, particularly each afternoon and evening, with locally gusty winds in and near storms, and a chance for patchy early-morning fog areawide. -GIH && .CLIMATE... Record High Temperatures: May 3: KGSO: 92/1959 KRDU: 93/1959 KFAY: 95/1913 Record High Minimum Temperatures: May 4: KGSO: 65/2022 KRDU: 68/1938 KFAY: 68/1942 && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Hartfield NEAR TERM...Hartfield SHORT TERM...Hartfield LONG TERM...Green AVIATION...Hartfield ####018005827#### FXUS61 KRLX 030625 AFDRLX AREA FORECAST DISCUSSION National Weather Service Charleston WV 225 AM EDT Fri May 3 2024 .SYNOPSIS... An approaching cold front brings showers and storms this afternoon into the weekend, then an active pattern continues next week. && .NEAR TERM /THROUGH TONIGHT/... As of 220 AM Friday... Moisture starts to increase this morning as high pressure fades to the east and a cold front approaches from the west. Warm air, transported into the area by southwesterly ahead of the front, should allow temperatures to rise into the 70s to 80s during the day. Showers will begin spreading across the area this afternoon, with scattered thunderstorms also likely to sprout up as moderate instability develops within the warm and moist environment. The frontal boundary then loiters to the west while a shortwave lifts across the region and sustains shower and storm activity within the CWA overnight. Precipitable water is expected to rise throughout the day, with values ranging from 1 to 1.75 inches this afternoon into tonight. This signals potential for some heavier downpours which could create localized problems mainly for poor drainage areas; however, widespread flooding is not anticipated given the fairly dry conditions leading up to today. Tonight's temperatures are expected to be mild, with lows in the 50s to 60s. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... As of 150 PM Thursday... Warm and humid conditions across the area Saturday, with showers and storms expected as a shortwave crosses the region. This will be followed by another wave that will cross the area on Sunday. With the warm and humid conditions in place/PW values progged to climb to around 1.5 to 1.6 inches, or well above normal for this time of year, will see heavy downpours at times. Light flow during the period, particularly on Sunday, could lead to some localized water issues, but overall threat for flooding is low, due to antecedent dry conditions, and continued greenup of vegetation. Temperatures on Saturday and Sunday will be cooler owing to the increased cloud cover/shower and storm activity, but it will still feel muggy. There is a possible brief lull or at least decrease in the precipitation expected late Sunday as the shortwave moves east of the area. && .LONG TERM /MONDAY THROUGH THURSDAY/... As of 1154 AM Thursday... Active weather continues for the extended period as another shortwave moves across the area on Monday. Focus then shifts to a low pressure system over the northern plains that will eventually move east over the Great Lakes and Canada, with an increasing zonal to southwesterly flow aloft taking hold across the area, and additional waves of low pressure developing and moving through the region. Showers and storms, with heavy downpours at times are expected, as well as an increasing threat for severe or organized storms, particularly Tuesday onward as shear and instability increase during the period. With the priming of soils over the weekend, and the threat for heavy rains next week, could see the potential for flooding issues increasing during this period, particularly Tuesday onward. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... As of 120 AM Friday... While VFR is expected to persist for much of the area, some areas of valley fog could form and cause localized restrictions to ceilings or visibilities early this morning. Any fog that does form will dissipate shortly after sunrise, then VFR and increasing mid to high level clouds are expected for the rest of the morning. Showers and thunderstorms develop across the area this afternoon and continue into tonight as a cold front approaches from the west. Periodic MVFR or worse restrictions will be possible during any heavier showers/storms later today and tonight. Calm to light winds are expected into the morning, then winds increase to 5-10kts generally out of the southwest during the day. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z SATURDAY... FORECAST CONFIDENCE: Medium. ALTERNATE SCENARIOS: Extent/intensity of fog may vary from the TAFs this morning. MVFR possible in heavier showers and thunderstorms this afternoon into tonight. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. DATE FRI 05/03/24 UTC 1HRLY 03 04 05 06 07 08 09 10 11 12 13 14 EDT 1HRLY 23 00 01 02 03 04 05 06 07 08 09 10 CRW CONSISTENCY H H H H H H H H H H H H HTS CONSISTENCY H H H H H H H H H H H H BKW CONSISTENCY H H H H H H H H H H H H EKN CONSISTENCY H H H H H H M M L H H H PKB CONSISTENCY H H H H H H H H H H H H CKB CONSISTENCY H H H H H H H H H H H H AFTER 06Z SATURDAY... IFR conditions possible in showers/storms at times from tonight into Sunday, and in stratus and/or fog Saturday/Sunday mornings. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...None. OH...None. KY...None. VA...None. && $$ SYNOPSIS...MEK/JLB NEAR TERM...JLB SHORT TERM...SL LONG TERM...SL AVIATION...JLB