####018004322#### FXPQ50 PGUM 032151 AFDGUM Area Forecast Discussion National Weather Service Tiyan GU 751 AM ChST Sat May 4 2024 .Marianas Synopsis... Latest satellite imagery is showing partly cloudy skies and isolated showers across the Marianas. Altimetry data indicates combined seas are 3 to 5 feet. && .Discussion... A fairly dry trade-wind pattern is expected through at least Tuesday. Subtle troughing in the flow may bring brief upticks in cloud coverage, but mainly isolated showers are expected. Towards the middle of next week, conditions may change depending on the development of features in western Micronesia and in turn, may see an increase in moisture and clouds pushing in from the south late next week. && .Marine... Gentle to moderate trade winds are expected to continue through the weekend and into next week. Combined seas of 4 to 5 feet are expected, then seas are expected to build as northerly swells enter the region. The first swell arrives by Sunday and the next push of north-northeast swell arrives by Tuesday, increasing seas up to 7 feet. The peak in north swell is expected to be around Wednesday, when surf along north-facing reefs may reach up to 7 or 8 feet. && .Fire weather... Only a trace of rain fell at the airport yesterday, allowing the KBDI to rise to 360, still in the moderate category. We may see a slight uptick in showers and clouds as a couple of trade-wind troughs pass through, but these features are not expected to bring significant rainfall over the next few days. && .Eastern Micronesia... Trade-wind convergence overnight has remained fragmented with scattered showers and isolated thunderstorms south and east of Majuro and between Kosrae and Pohnpei associated with weak convergence behind the troughs. Model analysis continues to show trade convergence shifting northward by early next week. The weak trough south of Majuro is expected to move over Kosrae around Monday with weak convergence generating scattered showers and isolated thunderstorms, then numerous showers and isolated thunderstorms on Tuesday at Pohnpei as the trough strengthens. Models show several weak troughs traversing within the region generating periods of scattered showers and isolated thunderstorm over the main islands with trade convergence strengthening around the latter part of the work week. Gentle to moderate winds are expected at Kosrae and Pohnpei with combined seas of 4 to 6 feet. For Majuro, moderate to fresh winds are expected through early next week, then weakening to gentle to moderate trades and combined seas of 5 to 7 feet. && .Western Micronesia... Satellite analysis overnight showed the Near-Equatorial Trough (NET) well south of the main islands of Yap and Palau. Scattered showers and isolated thunderstorms were observed along and north of the boundary overnight and early this morning. Model analysis overnight shows the NET will slowly lift northward toward Palau and Yap sometime early next week. Both the GFS and ECMWF try to develop a broad circulation along the NET, with the GFS being the most bullish with trying to develop the circulation as it moves north of the NET, while the ECMWF eventually dissipates the circulation as it moves toward Yap and Palau. Scattered showers and isolated thunderstorms are expected at Palau as weak trade-wind troughs impinging the NET through the middle of the next week. Isolated showers are expected at Yap with weak trade-wind troughs traversing the area, but unfortunately deep moisture will remain south of Yap State. For Chuuk, a strengthening trade-wind trough and trade convergence will bring numerous showers and isolated thunderstorms late this weekend into early over Weno. For the rest of the period, weak trade-wind troughs within the flow will generate chances for scattered showers and isolated thunderstorms. Gentle to moderate winds and combined seas of 4 to 6 feet are expected through early next week at Chuuk, Yap, and Palau. && .GUM WATCHES/WARNINGS/ADVISORIES... GU...None. MP...None. Marianas Waters...None. && $$ Marianas: Cruz Micronesia: Kelly ####018007718#### FXUS61 KOKX 032152 AFDOKX Area Forecast Discussion National Weather Service New York NY 552 PM EDT Fri May 3 2024 .SYNOPSIS... High pressure along the New England coast and into our area will remain nearly stationary into Saturday. A cold front then slowly approaches from the west on Sunday and moves across the area Sunday night into Monday. The boundary likely stalls to our south Monday afternoon through Tuesday before returning as a warm front Wednesday. A series of frontal waves may impact the area to end the week. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... Forecast on track this evening. A high amplitude upper ridge over the eastern third of the country will be slow to translate east through the first half this weekend. This will keep surface high pressure ridging down along the New England coast and into our area. Expect a light easterly flow to continue with varying amounts of cloud cover. Satellite imagery shows a fair amount of high clouds moving through the upper ridge axis. This could impact temperatures somewhat depending on the opacity. Lows will generally be in the mid to upper 40s, but around 50 for the NYC metro. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/... Not much change during this time as the forecast area will remain under an easterly flow at 10 mph or less. Varying amounts of high clouds will filter through the upper ridge over the area on Saturday, which works to the east Saturday night. Clouds will lower and thicken Saturday night with some fog possible toward daybreak Sunday. Warm advection rain on the backside of the ridge, ahead of an approaching warm front, continues to trend slower. Chances of rain Saturday night remain low and mainly after midnight. Temperatures during this time will at or just below normal. && .LONG TERM /SUNDAY THROUGH FRIDAY/... *Key Points* *An approaching front will bring rain Sunday into Sunday night, which ends early Monday morning. Rainfall amounts average one quarter to one half inch. *The front stalls to our south early next week with limited chances for showers through Tuesday. *Unsettled conditions are likely Wednesday through next Friday, although not a wash out. Several frontal waves are possible, which may bring periods of showers, but timing is uncertain. *Below normal temperatures Sunday should trend back above normal next week. Timing of the potential precip could impact temperatures late in the week. A shortwave associated with a larger upper low over Central Canada will try to break down the highly amplified ridging over the east coast to start the long term. The guidance has continued to show a slower trend to this process with the associated frontal system not moving through the area until Sunday night or early Monday. Rain associated with the front should start in the morning west of the NYC metro and then slowly spread eastward through the afternoon. This continues to look like mainly an overrunning rainfall with little to no elevated instability. Average amounts range from around one quarter to one half inch. The shortwave axis will push offshore later Monday with the front stalled to our south and west. Another highly amplified ridge builds across the Great Lakes in response to a large upper low over the Northern Plains and Northern Rockies. There are conflicting signals in the guidance for whether or not energy will traverse underneath the ridge towards the area Monday night. This potential energy would interact with the stalled front to bring another chance of rain. However, some of the global guidance weakens the energy with the height field becoming suppressed over New England in response to an upper low over the Maritimes. A weak high pressure should build towards New England which should keep any precip, if it were to develop, mainly near the coast closer to the stalled front. Have used the NBM for PoPs with just a low chance near the coast Monday night. A piece of the ridge builds overhead on Tuesday, so this should end up being a mainly dry day. The next forecast challenge will be for Wednesday through the end of the week. The stationary front to our south and west should begin lifting back north as a warm front on Wednesday. The parent low will be associated with the upper low over the Northern Rockies and Northern Plains, but there may be a few waves along the warm front. One of these may be enough to initiate some convection Wednesday afternoon or evening. The upper low then slowly moves east towards the Great Lakes to end the week. Several frontal waves may move across or just south the area keeping conditions unsettled. Timing of these waves is highly uncertain given a late Day 5 through Day 7 forecast, so have capped PoPs off at high chance for now. Sunday will be cool with rain and temperatures in the middle to upper 50s. Conditions should begin rising back above normal next week with temperatures in the 70s most afternoons away from the immediate coastline. Have followed the NBM deterministic, but it should be noted that there is a fair amount of spread in the guidance, especially later in the week due to the potential precip. && .AVIATION /22Z FRIDAY THROUGH WEDNESDAY/... High pressure remains along the New England coast and into our area through Saturday. VFR to start. Cigs may fall once again into late tonight into Saturday morning with potential stratus development, though confidence is too low to prevail at this time. However, added a TEMPO group for this possibility from 08Z-12Z Saturday. An E/SE flow with speeds around 10 kt or less will shift to the E tonight for the city terminals, and become light and variable for the outlying terminals. An occasional gust to around 20 kt is possible into the early evening hours. SE winds on Saturday with speeds at or below 10 kt. ...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty... There is uncertainty with the development of MVFR or lower clouds tonight. Best timing for this is between 08Z-12Z. OUTLOOK FOR 18Z SATURDAY THROUGH WEDNESDAY... Saturday: Mainly VFR. Low prob of patchy early AM MVFR stratus. Slight chance of showers and MVFR conditions in the afternoon, increasing chances overnight. Sunday...Likely showers, with MVFR or lower conditions. ESE winds G15-20kt. Monday...VFR. Tuesday... Mainly VFR. Chance of MVFR showers. Wednesday...MVFR or lower with a chance of showers. Detailed information, including hourly TAF wind component forecasts, can be found at: https:/www.weather.gov/zny/n90 && .MARINE... Sub-SCA conditions are forecast to start the weekend with high pressure along the New England coast maintaining an easterly flow across the waters. Winds will generally be around 10 kt. Winds and seas should remain below SCA criteria Sunday the middle of next week with a weak pressure gradient in place. There may be an increase in winds closer to 20 kt and seas building to around 4 ft, but conditions are expected to remain below SCA levels. && .HYDROLOGY... There are currently no hydrologic concerns through next week. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...None. && $$ SYNOPSIS...DS/DW NEAR TERM...DS/DW SHORT TERM...DW LONG TERM...DS AVIATION...JP MARINE...DS/DW HYDROLOGY...DS/DW