AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 500 AM EDT Thu Jul 5 2012 SYNOPSIS and Short Term (through Saturday)... Although POPS ended up being a little higher (~20%) on the 4th of July than we expected last NIGHT (especially over the FL Big Bend and Panhandle and SE AL), the early start to the CONVECTION certainly payed dividends for those with outdoor plans for the afternoon and evening hours, AS most of the activity was over with before the majority of the 4th of July festivities and fireworks were underway. Given the fact it was very difficult to make an accurate deterministic FCST until nearly the very last moment, we believe the situation worked out quite well. As has been anticipated for the past several days now, as the Upper Level RIDGE which brought our region the recent Heat Wave builds further off to our NW over the Plains, the N-NW FLOW from the Upper TROF Axis will setup across the CWA today and bring with it more UNSETTLED conditions. This will LIKELY consist of Sea Breeze induced showers and storms heading inland from late this morning into the afternoon hours, with possibly more organized convection pushing southward from later in the afternoon and evening. Whether or not we see a well organized MCS develop this evening or tonight is still uncertain at this time, but even with a favorable pattern in place for MCS development, it is quite possible that convection earlier in the day could sufficiently stabilize the ATMOSPHERE and limit later activity from forming. On Friday, while earlier in the week it appeared very likely that the Trof along the Gulf Coast would remain well established with another very unsettled day, it now appears that the GFS, NAM, and ECMWF all want to break it down a bit earlier than previously expected. Nevertheless, we will still carry 30-40% PoPs in the afternoon, but HIGH TEMPS appear poised to return to the middle 90s away from the coast. By Saturday, the Upper Level Pattern is expected to become even more diffuse, which should favor Hot and Humid conditions with mainly afternoon Sea Breeze induced showers and storms. At this time, have reduced PoPs to 20-30% from N to S across the CWA. && .LONG TERM [Saturday Night through next Thursday]...There is fairly high confidence in the overall evolution of the synoptic pattern over the CONUS from Sunday into Tuesday. Models are in fairly good agreement in this timeframe, with the 05.00z runs of the operational GFS and ECMWF showing 500mb heights within 10m of each other over most of the area east of the continental DIVIDE. The large, strong upper-level ANTICYCLONE will develop westward into the Intermountain West, while a SHORTWAVE TROUGH currently evident on water vapor loops over British Columbia should eventually dig into the Great Lakes on the backside of the retrograding ridge. This process should carve out a broad trough over the eastern CONUS. Much of the MID-upper level HEIGHT falls, and strongest JET stream winds, should be well off to the north near the Canadian border. Therefore, the northern portion of the trough should be fairly progressive while the southern extent could linger over the Southeast. The amplifying trough from Sunday into Monday should be accompanied by a cold FRONT pushing south through the Ohio River Valley and into the Southeast. HPC and many of the global models then stall the front somewhere near or just north of our area for the remainder of the week, with an ill-defined upper level trough axis situated west. This would place our area in increasingly deep southerly flow, a pattern that favors unsettled weather and increasing MOISTURE. Overall, not many changes were made to the extended forecast. PoPs for Sunday and perhaps Monday should continue to be dictated more by sea-breeze effects. Therefore, the PoPs Sunday-Monday remain a blend of sea-breeze CLIMATOLOGY and HPC Guidance. With more sporadic CLOUD cover well out in advance of the front, highs were kept a little warmer (mid 90s away from the coast). For Tuesday into Thursday, there should be increasing influence from synoptic-scale forcing mechanisms. This will likely result in more cloud cover, higher RAIN chances, and slightly cooler temperatures. Highs were nudged down into the lower 90s closer to climatological normals. && .Marine...A continuation of the typical summertime pattern of light winds and LOW SEAS appears to be in the cards for the bulk of the Coastal Waters Forecast, although an Upper Level Trough approaching from the north will increase the chances for showers and thunderstorms over the Marine Area for today and Friday. && .AVIATION...[through 06z Friday]... Mid-level cloud cover had quickly dissipated early tonight, and satellite and surface observations show that areas of FOG and low CIGS are beginning to SET in, particularly further west. IFR will be possible closer to SUNRISE, but for now we conservatively only took TLH and VLD down to MVFR given that fog seems to be developing more off to the west. Some brief reductions close to airport minimums can`t be ruled out at some of the other terminals (DHN, ABY, ECP) - and this has already been observed recently at DHN. While SCATTERED afternoon thunderstorms are expected, confidence in timing is low. Right now the thinking is that earlier activity (prior to 20-21z) will be concentrated closer to ECP in the western FL Panhandle, and the other terminals may be affected more in the late afternoon or early evening. For now, just VCTS was included. && .FIRE WEATHER...No fire weather concerns are anticipated for today or Friday as relative HUMIDITY should remain above 40%. Some interior areas of the Florida Panhandle may see relative humidity approach 35% on Saturday, but critical fire weather conditions are not currently anticipated. Increasing moisture and rain chances are on tap for the following week.