Area Forecast Discussion
Issued by NWS Tampa Bay Area, FL
Issued by NWS Tampa Bay Area, FL
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833 FXUS62 KTBW 151338 AFDTBW Area Forecast Discussion National Weather Service Tampa Bay Ruskin FL 938 AM EDT Sun Sep 15 2024 ...New UPDATE... .UPDATE... Issued at 935 AM EDT Sun Sep 15 2024 The low clouds and fog across parts of the area this morning is a bit slow to erode as winds still remain light but this should mix out over the next hour or so. Otherwise, it has been a quiet morning with just a few isolated showers across SWFL in the vicinity of lingering deeper moisture but much lower moisture levels across the central FL peninsula in the wake of the weak frontal boundary yesterday is supporting much drier conditions with no rain expected across the Tampa Bay area this afternoon. No changes needed to the ongoing forecast at this time with a rather seasonal Sunday ahead as highs reach the upper 80s to low 90s. && .DISCUSSION... Issued at 455 AM EDT Sun Sep 15 2024 Local weather conditions likely to remain relatively unchanged through the week due to a blocking pattern set up over the eastern U.S. Westerly flow aloft is in place over the peninsula this morning between west-east oriented troughing over the SE U.S. south of high pressure centered over SE Canada/Great Lakes, and a ridge axis south of the state over the S Gulf/N Caribbean. At the surface, a weak frontal boundary extends across the peninsula and into the Gulf from an area of low pressure off the GA/Carolinas coast, leading to N-NE flow north of the boundary and W-NW flow to its south. Despite lower PW values this morning generally between 1.3-1.8 inches over most of the area, a shallow moist layer over the lowest 1-2 km has allowed low clouds and patchy fog to fester again this morning, particularly for northern and central areas. Improving conditions expected as the morning progresses as daytime heating erodes the low cloud layer. Deeper moisture still in place across SWFL will favor the greatest chance of showers/embedded storms developing later this morning to the south of the boundary. Given the W-NW flow south of the boundary, expect convection to progress eastward away from the coast late morning through mid-afternoon with drier conditions through the remainder of the day. Elsewhere across the CWA, the only other notable PoPs look to be across areas north of I-4 from mid-late afternoon into the evening as Atlantic moisture advects into the area via N-NE flow north of the boundary. On Monday and Tuesday, the surface low off the SE U.S. coast is expected to move inland and across the Carolinas with the boundary continuing to linger across the peninsula, while the troughing aloft over the SE U.S. expands northward across the E U.S., dislodging the SE Canada/Great Lakes high. Moisture only gradually recovers over the peninsula, keeping PoPs mostly in the 30-50 percent range while continuing to favor highest PoPs transitioning inland through the afternoon hours. After a brief uptick in moisture around mid week, drier air again looks to work into the region during the latter half of the week as a result of N-NW flow around the area of low pressure aloft over the E U.S., leading to a reduction in PoPs late week into the weekend. Temperatures through the period look to remain fairly close to normal, with highs in the upper 80s to lower 90s. Triple-digit heat indices will still be likely during the afternoons, however they are expected to remain below advisory level, in part due to the periods of drier air expected over the upcoming week, which is to be expected as we approach the autumnal equinox a week from today. && .AVIATION... (12Z TAFS) Issued at 736 AM EDT Sun Sep 15 2024 Areas of low clouds and patchy fog are in place this morning with IFR/LIFR conditions to start the period but the fog should burn off around 13Z-14Z. After the fog burns off and low clouds lift, VFR conditions will generally prevail through the remainder of the day area-wide, though brief restrictions will be possible at times at KPGD/KFMY/KRSW due to the occasional sct TSRA. Otherwise, light ENE winds this morning will shift to the WNW later this morning and into the afternoon as the sea breeze develops with wind speeds around 5-10 kts throughout the day. && .MARINE... Issued at 455 AM EDT Sun Sep 15 2024 Drier air has settled over much of the waters this morning, however lingering moisture across the southernmost waters will keep isolated to scattered showers and storms off the southwest Florida coast. Winds will generally be from the northeast in the morning hours before shifting onshore as the sea breeze develops during the afternoon over the next couple of days. Winds will be 5-10 knots and seas less than 2 feet. && .FIRE WEATHER... Issued at 455 AM EDT Sun Sep 15 2024 A weak frontal boundary continues to sink slowly southward across the area with associated drier air resulting in lower rain chances, however a few showers and storms will remain possible in interior areas and southwest Florida. Minimum relative humidity values are expected to remain well above critical levels and given wet soil conditions from recent rainfall, fire danger is expected to remain low. && .PRELIMINARY POINT TEMPS/POPS... TPA 90 77 90 76 / 10 10 30 10 FMY 92 78 91 77 / 30 10 30 20 GIF 93 76 92 75 / 10 0 40 10 SRQ 90 77 90 76 / 10 0 20 10 BKV 91 73 90 72 / 20 10 40 10 SPG 90 80 90 80 / 10 10 20 10 && Sea Breeze Thunderstorm Regime For Sunday: 4 Sea Breeze Thunderstorm Regime For Monday: 4 For additional information on sea breeze regimes, go to: https://www.weather.gov/tbw/ThunderstormClimatology && .TBW WATCHES/WARNINGS/ADVISORIES... FL...None. Gulf waters...None. && $$ UPDATE/AVIATION/MARINE/FIRE WEATHER...Giarratana DECISION SUPPORT...Close UPPER AIR/CLIMATE...Close