####018009495#### FXUS61 KAKQ 040713 AFDAKQ AREA FORECAST DISCUSSION National Weather Service Wakefield VA 313 AM EDT Sat May 4 2024 .SYNOPSIS... A backdoor cold front pushes south and west of the area tonight. On and off shower chances are expected Saturday and Sunday. Summerlike conditions return to the area for next week with daily chances of showers and storms. && .NEAR TERM /THROUGH TONIGHT/... As of 310 AM EDT Saturday... Key Messages: -Dreary conditions across the entire forecast area today with extensive low-level cloud cover and scattered showers. Yesterday's backdoor cold front is situated just south of the FA early this morning. High pressure over New England is wedging cool, moist air into the Mid-Atlantic. With the front projected to stay S of the area today, expect a dreary Saturday. Latest radar shows scattered showers, primarily W of I-95. Chances for showers will continue through the day, but with the best forcing/lift and moisture remaining to the W, the highest coverage will continue to be over the piedmont. Closer to the coast, low level moisture from onshore flow will allow for patchy drizzle to continue through the morning. Minimal thunder is expected today, but could have a few rumbles in SW counties this evening. Easterly winds will be breezy E of I-95, especially near the coast, with gusts of 15-25mph. Temps today will be cool across far northern portions of the FA. Highs will struggle to even reach 60F. Far southern portions will likely see a few breaks in the clouds and winds will have a slight southerly component, allowing for warmer temps in the mid 70s. The gradient between these warmer temps and the rest of the FA will likely be sharp, so expect most will see cooler highs in the 60s. Showers in the far western counties increase in coverage overnight with lower end chances extending E to the coast. The front will start to move back N overnight, leading to stable if not slightly increasing temps late tonight/early Sunday. Lows will be in the low- mid 50s across the N and low 60s in the S. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... As of 330 PM EDT Friday... Key Messages: - Continued unsettled, but warmer, Sunday. - More humid on Monday with showers and storms areawide. The front is expected to lift back N Sunday into Monday, shifting the low-level flow to the S. These factors should act to scour out the dreary conditions seen on Saturday. However, still expecting shower redevelopment in the aftn hours as temps warm into the 70s and 80s and the residual front and a weak disturbance aloft remains near the area. An early look at some CAMs show that they are not particularly enthusiastic at widespread rainfall coverage, which makes sense given a lack of any focused areas of lift. Lows Sun night in the 60s. Upper heights begin building back N for Monday with high temps warming into the low 80s areawide. Despite the warmer temps, a lee trough is expected to develop in the aftn and evening hours. Combined w/ an approaching shortwave from the OH River Valley, showers and storms are expected to develop over the higher terrain in the afternoon and slide eastward into the evening. Models show around 1000 J/kg of CAPE developing with rather weak shear. Therefore, the severe threat looks relatively low, but cannot rule out a stronger storm or two. Soundings do show a rather saturated atmospheric column (PWATS potentially reach or exceed 1.5"), which could lead to some heavier downpours. Dew points also increase into the mid-upper 60s so the humidity will make it feel more like early summer. Shower/storm activity diminishes inland after midnight, but may linger closer to the coast overnight. Lows remain mild in the mid 60s. && .LONG TERM /TUESDAY THROUGH FRIDAY/... As of 335 PM EDT Friday... Key Messages... - A more summer-like pattern with warmer days and chances for late afternoon and evening showers and storms appears to be on the way for the middle to end of next week. We get into an almost summertime pattern by Tuesday as the ridge aloft builds overhead with afternoon/evening showers and thunderstorms each day being triggered by the lee side trough. The GFS and ECMWF both suggest the ridge breaks down slightly by Wed/Thu with stronger 500mb flow of up to 50 kt by Wed afternoon. Along with this, those models suggest weak shortwaves (likely of mesoscale origin from convection over the Ohio Valley and central plains) moving through the area. These convective complexes may also move through the region from the NW, but these features are notoriously hard to predict. Although we are talking about days 5-7, the relatively strong upper flow combined with relative steep mid level lapse rates of up to 7-7.5 C/km would suggest the possibility of severe weather. Instability will certainly not be a limiting factor as temps warm into the 80s and 90s every day. At this time, the synoptic pattern for severe looks most favorable Thursday with an approaching trough and the most robust CAPE. The CSU Machine Learning Probabilities have picked up on the aforementioned parameter space and suggest at least a slight risk for severe weather on Wednesday and Thursday for the entire area and Friday for southern/southeast areas. We continue to have plenty of time to monitor this, but the area may become more active by the end of next week. && .AVIATION /07Z SATURDAY THROUGH WEDNESDAY/... As of 145 AM EDT Saturday... Degraded flight conditions are expected to continue through the 06z/04 TAF period as IFR to LIFR CIGs have already overspread the terminals in the wake of a backdoor cold front (with E-NE winds of 10-15 kt with gusts to 20 kt). IFR/LIFR CIGs are expected through much of the night with perhaps some improvement on Sat (to 1000-2000 ft) with continued onshore flow. In terms of precipitation, scattered showers have spread over western portions of the area, and Richmond will likely see brief periods of light rain. Areas of drizzle are also possible through Sat AM. Shower chances continue on Saturday (highest PoPs at RIC w/ lesser chances near the coast). Outlook...Sub-VFR conditions expected at times through the weekend and even into Monday due to an unsettled weather pattern. Scattered showers and tstms are expected on both Sunday and Monday. A warmer, more summerlike pattern returns by Tuesday with chances for storms each afternoon/evening. && .MARINE... As of 710 PM EDT Friday... Key Messages: - Small Craft Advisories have been extended for the Chesapeake Bay and lower James River through Saturday night. - Small Craft Advisories for the seas north of the Virginia/North Carolina border have been extended until 1 AM Saturday. - Winds of 15 to 20 kt with gusts to 25 kt will diminish a bit later tonight into Saturday morning before increasing Saturday. Winds behind the backdoor cold front remain 15-20 kt with gusts to 25 kt this evening (lower across the NC coastal waters). Winds diminish some overnight but should still gust to 20 kt through the night. Winds ramp back up Sat afternoon into Sat night with gusts to 25 kt. Winds become ESE late Sat night as a warm front lifts N. Waves remain 2-4 ft during this time. Given the gusts to 20 kt between the two surges, have opted to extend SCAs through Sat night to account for both surges for the Ches Bay and Lower James. Additionally, with seas of 4-6 ft this evening N of the VA/NC border and persistent E flow, seas should be slow to subside to 4 ft tonight. As such, have extended SCAs for all coastal waters N of the VA/NC border until 1 AM Sat. The front lifts back N on Sunday, shifting winds to the SE/SSE. SSW winds return for Monday through the middle of next week (but likely remain sub-SCA).Southerly flow looks as though it will persist through most of next week with the next backdoor cold front possible some time Friday. && .TIDES/COASTAL FLOODING... As of 905 PM EDT Friday... Have maintained a Coastal Flood Statement for locations in the upper Bay as tides increase and stay just shy of minor flood stage overnight. Tidal anomalies continue to increase this weekend with minor to locally moderate flooding (at Bishops Head) possible across the middle and upper bay due prolonged onshore flow. Nuisance to minor flooding is possible up the James River as well Sat evening. Will likely need to upgrade the Coastal Flood Statement to a Coastal Flood Advisory across parts of the upper Bay for the Sat afternoon high tide. However, given that the upcoming high tide stays just below, will hold off for now. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...None. NC...None. VA...None. MARINE...Small Craft Advisory until 7 AM EDT Sunday for ANZ630>632-634. Small Craft Advisory until 4 AM EDT Sunday for ANZ638. Small Craft Advisory until 4 AM EDT early this morning for ANZ650-652-654-656. && $$ SYNOPSIS...SW NEAR TERM...AM SHORT TERM...SW LONG TERM...AM/SW AVIATION...AM/ERI MARINE...LKB/RMM/JAO TIDES/COASTAL FLOODING... ####018006592#### FXPQ50 PGUM 040713 AFDGUM Area Forecast Discussion National Weather Service Tiyan GU 513 PM ChST Sat May 4 2024 .Marianas Synopsis... Partly cloudy skies with isolated showers are seen on satellite this afternoon. Gentle to moderate trade winds prevail. Altimetry shows seas between 3 and 5 feet. && .Discussion... Not much happening across the Marianas for the next several days. A weak trough moving through the region brought a slight uptick in showers today. This trough looks to be west of the islands this evening, bringing drier conditions to the islands overnight. Another trough will approach the Marianas Sunday, bringing increase in cloud cover and another slight uptick in showers, though coverage looks to remain isolated. Around Thursday night into Friday next week, another more robust trough looks to move through the region, bringing a slight chance of thunderstorms to the Marianas. More stable and slightly drier conditions return for Friday into the weekend. && .Marine... Gentle to moderate trade winds will continue through the coming week. Combined seas of 3 to 5 feet are expected to slowly build over the next few days, reaching as high as 5 to 7 feet Tuesday. This is due to a north to northeast swell moving through the region. Latest model guidance is trending down with the heights of this swell, while shifting the direction more toward the northeast. The building north to northeast swell along with the trade swell is expected to produce a moderate risk of rip currents along east facing reefs for the next several days. The rip current risk is expected to become moderate along north facing reefs Sunday, also continuing for the next several days. With the north swell trending more toward the northeast, it is unlikely that the rip current risk will become moderate along west facing reefs. && .Eastern Micronesia and Chuuk... Trade convergence across the region remains fragmented, with showers primarily developing along troughs moving across the region and the weak convergence trailing behind the troughs. Chuuk Lagoon has been cloudy but showers have been isolated as the trough that was nearby yesterday continues to drift westward, and the trough currently pushing through Pohnpei and generating numerous showers across Pohnpei this evening, is not expected to reach Chuuk until about Sunday evening. Pohnpei will see showers decrease from numerous to scattered overnight, but convergence behind the trough should keep scattered showers at Pohnpei into next week. Majuro remains on the drier side, while Kosrae has been low-end scattered as weak convergence and trade-wind troughs have been passing south of Majuro and into Kosrae. Another trough has crossed the Date Line and is moving towards Majuro, and it looks like it will start to lift scattered showers into Majuro Sunday. Models also show trade-wind convergence slowly building and moving across Kosrae and Pohnpei, and then later into Chuuk, while also lifting northward into Majuro, promoting scattered to, at times, numerous showers, especially around Kosrae, Pohnpei, and Chuuk, next week. Thunderstorms are expected to remain fairly isolated across the region over the next few days due to the lack of strong divergent flow aloft. The northern islands of the RMI, such as Wotje, and islands north of 7N remain fairly dry and are expected to remain dry through the weekend and the middle of next week. As the convergent trade flow starts to lift north next week, some of these islands may start to see some scattered showers, although models vary greatly on potential rainfall amounts for the northern islands over the next 10 days, with some like the Canadian Ensemble showing about 1.30 inches, with the ECMWF being the most aggressive at about 4.3 inches, while the GFS sits roughly in the middle. Over the ocean, winds are expected to be from the northeast to east and mostly gentle to moderate, occasionally becoming fresh at times, especially around Majuro. Combined seas, as reported by altimetry, are around 4 to 6 feet at Chuuk, Pohnpei, and Kosrae and up to 7 feet around Majuro. Through the end of next week, not expecting any major changes in wind or sea conditions. && .Western Micronesia for Yap and Palau... Scatterometer and satellite data show that the Near-Equatorial Trough (NET) is still south of the main islands of Palau and Yap, extending westward from a buffer circulation near EQ160E and exiting the region near 3N130E, passing through a couple of very weak circulations, one south of Chuuk and the other well south of Yap state. Showers continue to develop along the north edge of the NET and weak trade-wind troughs, which so far remain south of the main islands of Palau and Yap Proper. Showers are expected to remain south of Palau through at least Monday and potentially as long as Thursday for Yap Proper and nearby islands as the NET and any passing trade-wind troughs are expected to remain near and south of 5N. This pattern starts to change next week as models show the NET lifting northward, as a broad circulation tries to develop within the NET. This will increase the potential for showers at Palau Monday night, but models have slowed the northward advance towards Yap Proper to Thursday night. As usual, the GFS becomes the most aggressive as it shows the circulation trying to develop as it pushes north and then northwestward into the Philippine Sea, while the ECMWF shows the circulation eventually dissipating and being reabsorbed back into the NET. What both of these models support is the potential for showers over Palau, and to a lesser extent at Yap, late next week. Winds over the ocean are expected to be fairly moderate and from the northeast to east over the next several days. Combined seas are expected to be around 4 to 5 feet through early next week, and this matches well with current heights reported by the buoys near Palau and Yap. Models are showing some north swell entering the region around midweek, but this swell is currently expected to be 4 feet or less, causing little change in overall sea heights, but may see some elevated north surf around Wednesday. && .GUM WATCHES/WARNINGS/ADVISORIES... GU...None. MP...None. Marianas Waters...None. && $$ Marianas: Kleeschulte Micronesia: Schank