Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 291339 AFDOKX Area Forecast Discussion National Weather Service New York NY 839 AM EST Tue Nov 29 2016 .SYNOPSIS... A pair of storm systems that will impact the area Today into Wednesday night. The first storm will move in today and depart this evening. The second storm will impact the area Wednesday through Wednesday night. High pressure will then slowly return for late week into the weekend, with only a weak cold frontal passage on Friday. Another low could impact the area Sunday night into Monday. && .NEAR TERM /THROUGH TONIGHT/... A couple of vigorous PAC shortwaves rounding a deep central US longwave trough will have a frontal system approaches the region this morning...with weak surface low development over or just NW of the region late today/this evening as it crosses. Light to moderate rain will overspread the region from west to east this morning. Best upper jet/shortwave forcing with this system will be to the NW, but difluence aloft and a 60-70 KT southerly low-level jet pumping in a +2-3 std pwat ahead/along a weak cold front and developing surface wave should support rain becoming moderate to heavy late this morning into afternoon. Axis of heaviest rain is still a bit uncertain based on surface wave track...but hill terrain of NE NJ/Lower Hudson Valley/Southern CT, and even northern LI should see rainfall enhancement in strong southerly flow regime. Weak elevated instability and strong dynamics may support some embedded thunder along the coast plain. In addition to rain...s/se wind gusts of 25-35 mph likely for coast and higher elevations late morning into early evening...with peak gusts to 40 mph possible. Weak cold front and llj/moisture axis moves east this evening...with a brief respite overnight. Patchy fog...locally dense...expected late today into Tonight with relatively high dewpoint airmass over the region. Temps well above normal with highs in the lower 60s along the coast...and well into the 50s interior. Lows tonight may not drop below normal highs for this time of year...50s coast and well into the 40s interior. && .SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/... After a brief respite early Wed morning...the second and potentially stronger frontal system approaches Wed and crosses through the region Wed Night. Forcing will be from 150kt jet streak and strong PAC energy rotating around the large closed low moving ne from the northern plains into Southern Ontario/Quebec Wed into Wed night. At the surface...primary low pressure tracks through the Great Lakes Wed/Wed Night with a warm front approaching the region during the day and triple pt low developing over or just NW of the region Wed Eve and intensifying as it tracks into New England Wed night Overrunning rain likely develop Wed morning. With closer mid/upper level forcing and low- level jet once again pumping in +3-4 std pwat...potential exists for another period of moderate/heavy rain Wed Aft/Eve in the vicinity of warm front and developing triple pt low. More pronounced marginal elevated instability should support embedded tstm activity during this time. With strong forcing and good convergence along the cold front..potential for organized fine line/squall line development Wed Eve with a conditional low prob of strong/severe wind gusts. This development is explicitly generated in several high-res models. At this point there is uncertainty on timing of shortwave energy...track of the triple pt low and placement of llj/warm sector...which are keys in determining heavy rain axis and any organized convective threat. Cold front pushes east after midnight as shortwave energy pivot through...bring rain to an end. Drying conditions expected late Wed Night on gusty westerly flow. && .LONG TERM /THURSDAY THROUGH MONDAY/... Upper low will be centered to our north on Thursday with a somewhat cyclonic flow aloft over our area. At the surface, high pressure builds in slowly. It`ll be a breezy day, but still with temperatures above normal as cold air advection will be weak and gradual on a west flow. Have bumped up high temp forecast a couple of degrees from a guidance blend. Cooler conditions on Friday as temps aloft drop, but mixing up to 850 mb still expected on a moderate westerly flow. Again, went a little above guidance for high temps. A weak cold front or trough of low pressure may move through during the afternoon, and this could cause a few sprinkles over the far NW zones and perhaps in the vicinity of the east end of LI. Not much of a change in the pattern for Saturday, just slightly cooler and will leave out any mention of sprinkles. There is still some pretty big differences among the global models regarding the next system to potentially affect the forecast area. ECMWF at least has trended toward GFS and CMC/GGEM with slowing down the onset of possible PCPN from low pressure developing in the southern states. Still the fastest among the three models, it doesn`t bring any PCPN over here until late Sunday night. With this trend, have removed PCPN from the forecast for the daytime on Sunday, but will still leave in a chance of PCPN for the night in the event the other models start speeding up this system. Will cap PoPs at chance for Monday with the given uncertainty in timing and track of this low pressure system. && .AVIATION /14Z TUESDAY THROUGH SATURDAY/...
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A warm front will continue to pass through the area today. VFR ceilings/visibilities will lower to MVFR this morning. Rain will continue to overspread the area from west to east. Conditions then lower to IFR as rain continues through the afternoon. The observed timing of lowering flight categories may be off a few hours from forecast. In addition, an isolated thunderstorm cannot be ruled out in the afternoon/early evening, primarily across the city and Long Island terminals. Some improvement in ceiling and visibility is possible after 00z Wednesday as the rain moves out, but as winds decrease fog and/or low stratus may redevelop early Wednesday morning with IFR/LIFR conditions possible. SE winds will increase through the morning, with gusts to 25-30 kt likely near the coast in the afternoon. A few gusts to 30-35 kt are possible in this region as well. LLWS is also likely near the coast this afternoon into the early evening hours. Winds veer to the SW and weaken tonight before becoming light and variable overnight. NY Metro Enhanced Aviation Weather Support... Detailed information, including hourly TAF wind component forecasts, can be found at: http:/ KJFK TAF Comments: Timing of changes in flight category this morning may be off by a few hours. KLGA TAF Comments: Timing of changes in flight category this morning may be off by a few hours. KEWR TAF Comments: Timing of changes in flight category this morning may be off by a few hours. The afternoon KEWR haze potential forecast is GREEN...which implies slant range visibility 7SM or greater outside of cloud. KTEB TAF Comments: Timing of changes in flight category this morning may be off by a few hours. KHPN TAF Comments: Timing of changes in flight category this morning may be off by a few hours. KISP TAF Comments: Timing of changes in flight category this morning may be off by a few hours. .OUTLOOK FOR 12Z WEDNESDAY THROUGH SATURDAY... .Wednesday...Rain and areas of fog. IFR conditions likely, LIFR possible in the morning. SE-S winds G25-30KT along the coast at night, with LLWS and thunder possible. .Thursday...Becoming VFR in the morning. W winds G20-25KT, diminishing at night. .Friday-Saturday...VFR. WNW Winds G20-25KT.
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&& .MARINE... SCA wind gusts expected to develop over all waters this morning...with a period of marginal gale gusts possible on the ocean this aft/eve. For the nearshore waters...the gale threat appears to be more of an occasional gust. Any embedded thunderstorms this aft/eve could bring down some locally higher gusts. Seas should build to 8 to 12 ft on the ocean by this evening. Areas of fog will also be possible late today into Tonight as a high dewpoint airmass moves over the waters Ocean seas on Wed should remain elevated through the daytime Wed. Winds also increase Wed Aft/Wed Eve as the next storm approaches, with SCA winds gusts likely on all waters, and possibly reaching gale force on the ocean Wed Night just ahead of an approaching cold front. Embedded thunderstorms could bring down some locally higher gusts...with even potential for an organized squall line. SCA conditions remain likely on the ocean waters through Saturday night. Elsewhere, periods of 25 kt gusts will be possible primarily over the eastern sound and bays through Friday night, with a chance that all non-ocean waters remain below criteria on Saturday. && .HYDROLOGY... Around 1-1.5 inches of rainfall is expected today into this evening...with locally higher swaths of 2+ inches possible. The main threat is for minor urban and poor drainage flooding...with a low prob of flash flooding if 2+ inch swath aligns over urban corridor. Another 1-2 inches of rainfall is possible Wed into Wed Night. Once again the main threat will be for minor urban and poor drainage flooding. No significant PCPN expected from Thursday through at least Sunday. A chance of PCPN returns Sunday night into Monday. && .CLIMATE... Much needed precipitation is expected across the Tri-State area Tuesday into Wednesday which should aid in cutting the significant departures from normal we have seen so far for this year. Through yesterday Central Park was 9.16 inches below normal for the year to date with respect to precipitation. Looking closer at precipitation stats, so far this year only 36.35 inches of precipitation has fallen at The Park. Since records started in 1869 only 41 calendar years, or roughly 28 percent, have had less than 40 inches of precipitation for the calendar year. Since 1990 though this has only happened twice: in 2001 The Park measured 35.92 inches and in 2012 The Park measured 38.51 inches. Going back to 1970 another 3 years would join this list - 1970, 1981 and 1985. For some of other major climate stations, the last 2 years combined have also been significantly dry. Newark Airport only saw 38.98 inches of precipitation last year and this year so far was at 32.41 inches. The last time Newark had 2 consecutive years with less than 40 inches of precipitation was in 1980 and 1981 which saw a significant drought in North Jersey. At Bridgeport, last year a total of 35.03 inches of precipitation was measured and this year`s total stands at 33.30 inches. Bridgeport has not had two consecutive years with less than 40 inches of precipitation since the stretch from 1985-1988. The bottom line...we`ve been dry and it will be interesting to see how things finish up the year. This will be something for us to watch during December. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...Small Craft Advisory until 7 PM EST this evening for ANZ335- 338-345. Small Craft Advisory until 10 PM EST this evening for ANZ330- 340. Small Craft Advisory until 6 PM EST Wednesday for ANZ350-353- 355. && $$ SYNOPSIS...JC/NV NEAR TERM...NV SHORT TERM...NV LONG TERM...JC AVIATION...FEB/JMC MARINE...JC/NV HYDROLOGY...JC/NV CLIMATE... is the U.S. government's official web portal to all federal, state and local government web resources and services.