AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 820 PM EST Fri Dec 2 2011 .SYNOPSIS... AT UPPER LEVELS... The large scale longwave pattern is highlighted by a deep positively tilted TROUGH over WRN states with 550dm closed LOW over AZ...a deep layer RIDGE over CNTRL states...SE region and adjacent Wrn Atlc, and a trough over NE states. RUC shows a deep water vapor return from the Gulf of MEX along wrn periphery of ridge along Wrn Gulf but clouds should remain west of local area. All this translates to continued FAIR, dry and cool weather over NE Gulf region. This reflected in area 00Z RAOBS. i.e. TAE with 0.17 inch PWAT with light ENE FLOW below and WNW winds above H6. During the next 24 HRS, AZ low will deamplify AS it accelerates NEWD THRU NM...CNTRL Plains reaching Upper MS Valley/Upper Great Lakes early Sunday. Parent trough will deepen EWD. This allows for the building of DOWNSTREAM ridge from Yucatan NEWD thru Gulf of Mex and into N FL and SE region with rising heights and warming TEMPS. AT LOWER LEVELS... HIGH PRESSURE centered over SRN Great Lakes dominates SE region maintaining a NE flow. Looking UPSTREAM, main feature is low over Cntrl Canada with trailing FRONT SWWD over Plains to low over NEB. By early SAT...low shifts newd shift front ewd now extending from Upper Great Lakes swwd thru MO and W TX by early sat. A warming trend is forecast for the rest of the weekend as the high moves into New England overnight and drifts off coast during Sat and Sun before ridging SSW down ERN seaboard and into SE coastal area tightening local gradients and VEERING winds to produce BREEZY northeast to east flow. This will also bring some low level MOISTURE WWD from the Atlc. && .NEAR TERM...(Rest of Tonight into early Saturday) High pressure remains the dominant feature in the local weather pattern. The ridge is forecast to shift more NE of the area overnight, which may allow just enough of a light breeze at times to keep temperatures from falling as much as last NIGHT. As a result, we are not expecting a WIDESPREAD FREEZE, although with inland DEW points in the low to MID 30s and LIKELY light winds and clear skies, areas of FROST are still likely in the typically colder locations away from urban areas. .SHORT TERM... (Saturday through Monday) A deep layer ridge will remain situated along the U.S. east coast through Monday, resulting in a continuation of the FAIR weather of the past few days. After one more potentially frosty morning Saturday, a warming trend will begin in earnest. Lows will be in the 40s Sunday, and around 50 on Monday. Highs will be near average levels (upper 60s north and at the beaches, lower 70s south) Saturday, lower to MID 70s Sunday, and mid to upper 70s Monday (with the SAME TEMPERATURE distribution mentioned for Saturday). .LONG TERM... (Monday night through next Friday) The extended period begins with a broad, positively tilted, upper level TROUGH covering the entire country (with the exception of the extreme southeastern U.S.). At the surface, a southwest to northeast extending surface ridge covers the eastern part of the country with a surface LOW across the northern Great Lakes and Ontario. A frontal boundary extends southwest from the aforementioned surface low, into a surface trough over the Deep South. As the upper level trough holds its position, deep layer meridional FLOW will prevent the surface FRONT from moving too quickly east. It won`t be until sometime around Tuesday afternoon, when a SHORTWAVE diving out of the northern Plains helps advance the entire system eastward, pushing the front through our area and drying us out by Wednesday afternoon. No severe weather is expected with this system, in fact we may not even see any THUNDERSTORM development over land as INSTABILITY is severely lacking. Additionally, with the best DYNAMICS not quite aligned with the surface front, expect the front to weaken as it approaches, and passes over our area. This means very limited RAINFALL for us as well. At this time, guidance suggests around a half of an inch for our western counties, and less than a quarter of an inch likely for counties east of a line from Albany south to Tallahassee. Temperatures will be moderated by easterly, followed by southerly, flow before the frontal passage. Expect above average temperatures with highs in the 70s and lows in the 50s. Behind the front, temperatures will FALL into the 30s once again. && .AVIATION...VFR conditions will prevail. Winds will shift to easterly tomorrow as the high pressure area nears the Mid Atlantic Coast. && .MARINE...The PERSISTENCE of the high pressure ridge situated along the U.S. eastern seaboard will maintain a rather tight pressure GRADIENT over the coastal waters through Monday. At 8 PM EST offshore buoys already around 15 knots and should increase to SCEC levels before midnight. So exercise caution has been headlined for rest of tonight for all but the Apalachee Bay. Winds will peak perhaps late Saturday night or early Sunday with marginal ADVISORY winds (around 20 KT) over portions of our coastal waters. Otherwise, winds will continue to straddle the exercise caution threshold through Saturday evening.