Surface analysis this morning shows two warm fronts over our area- the synoptic front along the FL-GA border that extends NWward across central AL and an offshore warm front around 50 nm offshore along the FL coastline. A cold front lies to our west across the Arklatex. Moisture is plentiful with southerly flow at the surface and deep layer southwesterly flow continuing to bring warm, moist air from the Gulf. The 12Z TAE sounding showed a PWAT of 1.68, which is 2 standard deviations above normal. Some spots in the western FL Big Bend having already received about 2-3 of rain. Continued heavy rainfall on top of already wet soil makes flooding is a main concern with this system. Rainfall totals for today and tomorrow are expected to be 3-5.5 with isolated amounts even higher possible. There is a severe weather threat with these storms, with the potential for isolated tornadoes, damaging straight-line winds and hail. Model MLCAPE for the warning area is around 500 J/kg with 0-6km shear of 40-50kts. This high shear low CAPE environment will be favorable for supercell development. The 12Z sounding shows steep lapse rate from 800-550mb as well. Our low level (0-1km) shear of 15-20kts, which will support tornado development in supercells that form, especially if they form behind the currently offshore warm front. Overnight, as the main squall line approaches, the low level jet will set up over our area, which will mean the potential for an isolated tornado to be embedded in a QLCS line and and will increase the potential for damaging straight-line winds. .Short Term [Tonight Through Thursday]... The severe weather and flooding threat which is already beginning in earnest across the region today will continue through the area tonight and linger into Wednesday, will result in the greatest potential for additional severe storms to linger into tonight. However, since the ground will already be well saturated from earlier rainfall from the past several days, the flooding threat on Wednesday could still be quite significant, especially across eastern portions of the CWA where the deep layer moisture will be last to leave the region. We will finally experience a respite on Wednesday night and Thursday as a strong cold front plows through the region and brings a return to fair, cool, and dry weather just in time for Christmas over the CWA. .Long Term [Thursday Night Through Tuesday]... The fair, dry, and seasonable weather that will be building in behind the cold frontal passage on Wednesday night should hold until the end of the week. By next weekend and early next week, however, a new corridor of moisture is expected to setup between a ridge of high pressure over the Carribean and a developing upper trof over the lower plains. While this pattern will will keep temperatures above climatology for the entire period, it will also begin to increase rain chances over the region once again, as a potentially large area of deep layer moisture is funneled NE in between these two systems. .Aviation... [Through 12Z Wednesday] LIFR ceilings and visibilities will gradually improve this morning but ceilings will likely be in the IFR range for much of the day. Widespread showers and thunderstorms should be expected at all terminals throughout the day and night. .Marine... A developing low pressure system off to our west will continue to increase onshore winds across the coastal waters today. These winds and seas will gradually reach Small Craft Advisory levels by this evening while conditions continue to become more hazardous. Winds and seas will then gradually diminish behind the passage of the next cold front on Wednesday night and Thursday when all headlines will be able to be removed. .Fire Weather... Hazardous fire weather conditions are not expected for the next several days. && .Preliminary Point Temps/PoPs... Tallahassee 68 64 72 43 62 / 100 90 80 30 10 Panama City 68 66 68 43 59 / 100 90 70 20 10 Dothan 69 63 67 40 59 / 100 90 60 20 10 Albany 69 63 71 41 60 / 100 90 80 30 10 Valdosta 70 63 73 46 61 / 90 90 90 40 10 Cross City 72 64 74 48 64 / 70 90 90 40 10 Apalachicola 68 67 70 45 59 / 100 90 80 30 10 && .TAE Watches/Warnings/Advisories... FL...Flash Flood Watch through Wednesday evening for Calhoun-Central Walton-Coastal Bay-Coastal Dixie-Coastal Franklin-Coastal Gulf-Coastal Jefferson-Coastal Taylor-Coastal Wakulla- Gadsden-Holmes-Inland Bay-Inland Dixie-Inland Franklin- Inland Gulf-Inland Jefferson-Inland Taylor-Inland Wakulla- Inland Walton-Jackson-Lafayette-Leon-Liberty-Madison-South Walton-Washington. RIP CURRENT RISK through late tonight for Coastal Bay-Coastal Franklin-Coastal Gulf-South Walton. GA...Flash Flood Watch through Wednesday evening for Baker-Ben Hill- Berrien-Brooks-Calhoun-Clay-Colquitt-Cook-Decatur-Dougherty- Early-Grady-Irwin-Lanier-Lee-Lowndes-Miller-Mitchell- Quitman-Randolph-Seminole-Terrell-Thomas-Tift-Turner-Worth. AL...Flash Flood Watch through Wednesday afternoon for Coffee-Dale- Geneva-Henry-Houston. GM...Small Craft Advisory from 7 PM this evening to 1 PM EST Thursday for Apalachee Bay-Coastal waters From Ochlockonee River to Apalachicola FL out to 20 NM-Coastal waters from Suwannee River to Keaton Beach FL out 20 NM-Coastal waters from Apalachicola to Destin FL out 20 NM-Waters from Suwannee River to Apalachicola FL from 20 to 60 NM-Waters from Apalachicola to Destin FL from 20 to 60 NM. && $$ NEAR TERM...MOORE SHORT TERM...GOULD LONG TERM...GOULD AVIATION...MOORE MARINE...GOULD FIRE WEATHER...HARRIGAN HYDROLOGY...HOLLINGSWORTH
Posted on: Tue, 23 Dec 2014 15:38:44 +0000
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