Area forecast discussion National Weather Service Mount Holly New Jersey 113 PM EDT Wednesday Oct 1 2014 Synopsis... low pressure will redevelop off the New England coast through Thursday as high pressure over eastern Canada builds in from the northeast. A strong low pressure system over the central United States will move northeastward into Ontario by Friday and its associated strong cold front will move through the region Friday night into Saturday. High pressure will build in behind the departing front. Another cold front will cross the region around Monday. && Near term /until 6 PM this evening/... next estf update we are going to continue minimal probability of precipitation mainly around the edges of our County Warning Area. There are showers both west and northeast of our area. The former should pass mostly to our west, while the latter is struggling to arrive in northern New Jersey. Cloud condensation level based cumulus are forming, so no big changes to other parameters needed. Upper low crossing PA/New Jersey today with moist cyclonic flow. Overcast skies this morning should brighten or thin a bit this afternoon to reveal a little sunset. Temperatures/winds/dews are a 50 50 blend of the 100z/1 NAM/GFS MOS. . && Short term /6 PM this evening through 6 am Thursday/... there may be evening partial clearing before bl relative humidity saturates and develops lows clouds and possibly patchy fog. GFS MOS temperatures look far too cold since the low pressure system is far to the east and the cold air advection is weak. Used the NAM MOS temperatures for lows which are several degrees warmer than the GFS MOS. Even these were raised a degree or two. Dews were NAM MOS. Winds were a 50 50 blend of the GFS/NAM MOS Probability of precipitation were blended GFS/NAM MOS and lowered in the SW portion of the forecast area using the 21z/30 sref. && Long term /Thursday through Tuesday/... an area of high pressure over the can Maritimes will nose westward over the area on Thursday and expect a dry day but abundant cloudiness as Ely flow will persist. This high will remain in place for Thursday night into Erly Friday with low pressure well off the CST of new eng. Attention then turns to the central Continental U.S. Where a potent low pressure system will take shape beginning Thursday night. This low will move north-northeastward and strengthen as it moves into or toward Ontario on Friday. The models all agree on the fact that this low develops and moves into or toward Ontario during this time frame, they differ a bit on the details, as should be expected. The GFS, NAM/WRF and CMC have a single low structure and bring the low into Ontario by 03/18z. On the other hand, the European model (ecmwf) has a double low structure at 03/18z and is significantly weaker at this time frame (by about 10 mb) than any other model. It then is interesting that by 78 and 84 hours the European model (ecmwf) model has the strongest solution with the low, but it is further S and east with the low center than the other models. The cold front associated with this low will begin moving eastward and there could be some precipitation in western areas by sunset Fri, though confidence is low. Precipitation chances will increase from west to east Friday night and there are timing diffs with the models as well. The GFS and NAM/WRF generally keep the heaviest precipitation west of the I-95 corridor through daybreak Sat while the European model (ecmwf) and CMC are further east. The GFS then brings the heavier precipitation through during the morning hours while the European model (ecmwf) is about 6 hours faster. Then precipitation ends from SW to NE during the day behind the cold front passage as a wind shift from east to west-northwest brings in drier air. There is sill enough uncertainty in the models to keep confidence lower than average. The European model (ecmwf) is often too slow with frontal timing, so its interesting that it is the faster solution here. One noticeable trend in the 01/00 guidance is improvement in the second half of Sat, so have lowered probability of precipitation during this time for this forecast issuance. With that said, high pressure moves in behind cold front passage and Sat night through Monday look dry. Another weak cold front will cross the region on Mon, but at this time not enough confidence to put in poops as the European model (ecmwf) is dry while the GFS has some low probability of precipitation. On Tue, there could be some additional precip, which the models develop differently. The European model (ecmwf) tries to develop some from an area of low pressure which takes shape from some southern stream energy over the southeastern states and moves northeastward. The GFS has some northern stream and southern stream energy and possibly another weak frontal passage. Again, for now will just carry some low probability of precipitation. Temperatures will generally average near nrml, except for sun in the cold advection behind the strong fropa, where temperatures will average much below normal. && Aviation /18z Wednesday through Monday/... the following discussion is for kphl, kpne, kttn, kabe, krdg, kilg, kmiv, kacy and surrounding areas. 18z tafs will continue the idea of some VFR conditions this afternoon, but then predominately MVFR tonight into Thursday morning. This afternoon into early evening, mainly MVFR ceilings at coastal airports and terminals, borderline MVFR/VFR ceilings for the i95 corridor and higher terrain airports and terminals and predominately VFR ceilings at krdg and kabe. Winds should be northeast at 5 to 10 knots. Tonight predicting a MVFR ceiling to reform at all airports and terminals, closest to IFR levels at the coast. Because of the predicted cig, we did not forecast that much fog and mainly at the more rural terminals. Winds should be light from the north. On Thursday we are reversing the process with a slightly slower improvement to VFR ceilings as moisture from New England at the MVFR level continues to move into the region. Winds should be slightly more from the north than northeast at speeds of around 10 knots. Outlook... Thursday afternoon...VFR. MDT to high confidence. Friday..VFR Erly. Possible MVFR west late. Rain chances late west. MDT confidence. Friday night...MVFR/IFR with increasing rain chances from west to east by daybreak. Rain could be heavy at times, with approaching cold front. MDT confidence, though low to MDT on frontal posn. Sat...MVFR/IFR early in rain, heavy at times...increasing to VFR. Rain ending from west to east during the mrng/afternoon. Cold front passage late morning Erly afternoon from west to east and wind shift from southeast to west-northwest. MDT confidence. && Marine... there has been a steady rise in seas at buoy9 to near Small Craft Advisory conditions. Given Texas tower seas are also slowly rising, we will extend the Small Craft Advisory farther down the coast. Two weeks after restoration of a lengthy buoy 44065 outage...data transmission topped at 4pm this past Tuesday afternoon. Ndbc has been contacted and they will let US know what the problem is. Basically NE flow continues through tonight with maximum gusts around 20 knots. Seas build to near 5 feet and generally 1-2 feet Delaware Bay. Outlook... Thursday...Ely flow will persist and there could be Small Craft Advisory conds once again, with a better chance over the northern waters. However, Thursday is a marginal day and the latest guidance indicates we may fall just short. Thursday night into Friday...Small Craft Advisory will likely be needed at some point during this period as seas increase ahead of an approaching cold front. Sat...strong cold front passage. Windshift to northwest or west-northwest. Seas will increase further and Small Craft Advisory will continue. Best chance for Small Craft Advisory wind during this time frame. && Climate... monthly clm's have been run. && Phi watches/warnings/advisories... PA...none. New Jersey...none. Delaware...none. Maryland...none. Marine...Small Craft Advisory until 6 am EDT Thursday for anz450>455. && $$ Synopsis...nierenberg near term...drag/gigi short term...drag long term...nierenberg aviation...gigi/nierenberg marine...drag/gigi/nierenberg climate...
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