South Florida Water Management District Weather

South Florida Water Management District Weather

10:01AM Friday, July 01, 2022 (tbk)

…SOUTHEASTERLY STEERING WINDS & GOOD MOISTURE FAVOR GREATEST AFTERNOON RAINS OVER THE WESTERN HALF OF THE SFWMD THIS AFTERNOON TO EVENING…DRIER AIR IN THE EAST KEEP RAINFALL AT A RELATIVE MINIMUM…

…MID-LEVEL HIGH PRESSURE STRENTHENS THIS WEEKEND…AN EASTERLY TO SOUTHEASTERLY STEERING WIND REGIME FAVORS MORNING RAINS IN THE EAST & GREATER AFTERNOON RAINS OVER THE INTERIOR & THE WEST SAT-MON…

…THE NORTHERN END OF A TROPICAL WAVE PASSING THROUGH THE SFWMD ON TUES & WEST OF THE AREA ON WEDS COULD CAUSE ENHANCED RAINS…LOCALLY HEAVY RAINFALL POSSIBLE…EVEN OVER A BROADER SCALE…

…SUBSTANTIALLY LESS RAINFALL POSSIBLE THURS NEXT WEEK…

Quantitative Precipitation Forecast	24Hr Begin 7AM Fri	Local Max	24Hr Begin 7AM Sat	24Hr Begin 7AM Sun	24Hr Begin 7AM Mon	24Hr Begin 7AM Tue
Upper Kissimmee	.56	5"	.19	.25	.27	.20
Lower Kissimmee	.25	4"	.10	.05	.16	.19
Lake Okeechobee	.20	2.5"	.14	.04	.08	.17
East Agricultural Areas	.11	1.5"	.27	.09	.09	.31
West Agricultural Areas	.26	3"	.30	.14	.12	.39
Conservation Areas 1&2	.05	<1"	.11	.06	.09	.34
Conservation Area 3	.09	1"	.14	.10	.12	.41
Martin/StLucie Counties	.12	2"	.21	.07	.10	.23
East Palm Beach County	.04	1.5"	.13	.04	.09	.29
East Broward County	.03	<1"	.08	.01	.08	.35
East Miami-Dade County	.03	<1"	.09	.01	.10	.40
East Caloosahatchee	.50	5"	.32	.17	.14	.32
Big Cypress Preserve	.23	3"	.23	.17	.17	.47
Southwest Coast	.50	5"	.34	.28	.30	.54
District Overall	0.25	-	0.20	0.12	0.15	0.33
Forecast Confidence	Mod-High	-	Mod-Low	Mod-Low	Mod-Low	Mod-Low
Most Likely Range	0.15-0.35	-	0.10-0.31	0.07-0.26	0.06-0.30	0.21-0.45

Synopsis: A surface trough of low pressure along the southeast coast of the U.S. is expected to hang back over north Florida through today while an upper-level low that was near the Florida Keys yesterday sinks well south of the area over Cuba and the northern Caribbean Sea. Abundant and deep moisture surrounding and pooling south of the surface trough will extend southward through the northwestern half of the SFWMD this afternoon while subsidence (or sinking air) around the upper-level low causes a warming and drying of the mid-levels of the atmosphere over the southeastern part of the SFWMD later today. The result of these factors should be a QPF that shows a good or even widespread coverage of rainfall over the western to northwestern half of the SFMWD from afternoon showers and thunderstorms, with the heaviest rains likely from the western interior through the Kissimmee Valley where the steering winds will be turn from southeasterly around Lake Okeechobee to southwesterly over the far north. Much drier conditions with little substantive rainfall are expected in the southeast where a more stable atmosphere and a drying are seen occurring soon. The median large areal average rainfall in the southeast is under a tenth of an inch and perhaps even well under that in most locations while a quarter to around half of an inch is the median large areal average rainfall over the northwestern half of the SFWMD, values all at or above the daily climatological average. The 10% exceedance or reasonable worst-case scenario is half to three quarters of an inch over the wettest areas today, with the highest potential probably over the Kissimmee valley where the steering winds are more convergent and the moisture supply greater. Next, a quick-moving but strong upper-air disturbance passing through the Great Lakes and northeastern U.S. today and Saturday will temporarily erode the mid-level high pressure that has been dominating the southern U.S. recently. While less overall rain seems most likely on Saturday, the forecast spread or degree of model differences is rather wide, indicating an uncertain forecast regarding how much rain to expect. However, the steering wind regime will generally favor less rain in the east and greater rains over the interior and the west. Beginning Sunday, the mid-level high pressure will rebuild, centered near the northern Gulf Coast, and is most likely to result an overall drier pattern for the SFWMD on Sunday and Monday. A general easterly to east-southeasterly steering regime around the high pressure will again favor morning rains in the east and greater rains over the interior and the west, albeit quite a bit less observed Thursday and Friday of this week. Next, a tropical wave currently approaching the Windward Islands could show signs of organization until it reaches the eastern/central Caribbean Sea this weekend, where it will then encounter strong upper-level winds that will make any further development unlikely. However, the northern end of the tropical wave is forecast to pass through the Florida Straits and south Florida on Tuesday and move past the area into the southeastern Gulf of Mexico on Wednesday. The moisture envelope and increased instability accompanying the wave as it passes through southern Florida and the Florida Straits should cause a large increase of total SFWMD to above the daily climatological average both Tuesday and Wednesday, with main focus of the enhanced rains around and south of Lake Okeechobee on Tuesday and over western areas on Wednesday. The favorable large-scale conditions associated with the tropical wave’s passage will mean an increased risk of locally significant rainfall totals, possibly even over a broader scale and more than currently forecast. After mid-week next week, the tropical wave will be well west of the area and the strong mid-level ridge and its associated subsidence will probably make for a much drier forecast, with rainfall below or well below the daily climatological average. For the week ending next Friday morning, total SFWMD rainfall is most likely to be below or slightly below the long-term weekly average. However, given the higher degree of uncertainty regarding the rainfall forecasts the next few days and the possibility that rains associated with the tropical wave could be greater, total weekly SFWMD rainfall could be near to somewhat above average if the upper quartile of model solutions verify.

Friday: A few showers in the east this morning and then isolated or widely scattered showers or isolated thunderstorms through the eastern interior through early or mid-afternoon before rain chances diminish. Then scattered to numerous showers and thunderstorms over the northwestern or western half of the SFWMD, with heaviest rains from the western interior through the Kissimmee Valley this afternoon and evening. Locally significant rainfall accumulations are possible over these areas. A lake ‘shadow’ could form northwest or west-northwest of Lake Okeechobee over which significantly less rainfall, and possibly little to none, would occur relative to the surrounding areas. Evening rains over the northwestern half of the SFWMD should diminish, followed by a slight chance of east-coast showers overnight. Mainly ESE to SE winds 5 to 15 mph but lighter with calm conditions at some inland locations.

Saturday: A chance of widely scattered shower activity in the east during the morning, followed by decreasing rain chances by early or mid-afternoon. Then afternoon showers and thunderstorms developing over the interior of the SFWMD and the west/west coast, ending during the early evening. A localized, significant rainfall accumulation is possible over the west. A lake ‘shadow’ could form northwest of Lake Okeechobee over which significantly less rainfall, and possibly little to none, would occur relative to the surrounding areas. Evening rains diminishing, followed by light-east coast showers possible overnight. E to SE winds 5 to 15 mph, with occasional gusts to 20 mph along and near the east coast through the Florida Keys.

Sunday: Little rain in the east, except for isolated morning showers. Then decreasing rain chances during the afternoon. Afternoon showers and thunderstorms, widely scattered or scattered in coverage, likely over the interior of the west, lasting into the early evening in some cases before diminishing. A lake ‘shadow’ could form west-northwest of Lake Okeechobee over which significantly less rainfall, and possibly little to none, would occur relative to the surrounding areas. Isolated east-coast showers overnight. E to ESE winds 5 to 15 mph.

Monday: Widely scattered shower and isolated thunderstorm activity in the east during the morning, followed by decreasing rain chances. Then greater interior and western rains during the afternoon to early evening. A lake ‘shadow’ could form west or west-northwest of Lake Okeechobee over which significantly less rainfall, and possibly little to none, would occur relative to the surrounding areas. Evening rains diminishing, followed by a few east-coast showers overnight. Mainly E to ESE winds 5 to 15 mph, backing E to ENE by Tuesday morning.

Tuesday: An increase of total rainfall to at or above the daily climatological average due to a tropical wave passage. Scattered to numerous showers and thunderstorms in the east during the morning and then continuing off and on during the day. Then heavier afternoon rains developing over the interior and the west, especially from around Lake Okeechobee southward. With the wave’s passage, there will be elevated risk of locally heavy rainfall and potentially on an even broader scale. A lake ‘shadow’ could form west-northwest of Lake Okeechobee over which significantly less rainfall, and possibly little to none, would occur relative to the surrounding areas. Although rains should diminish in coverage during the evening, additional showers and isolated thunderstorms could move onshore the east-coast overnight. ENE winds very thing in the morning 5 to 15 mph, becoming E to SE by afternoon and then SE and light overnight.

Wednesday: A continued good chance of rainfall at or above the daily climatological average the northern end of a tropical wave passes to the west. Scattered to numerous afternoon showers and thunderstorms in the east during the morning. Then numerous showers and thunderstorms over the interior and the west, with western area seeing an above-normal risk of excessive rainfall, perhaps even on a broader scale. A lake ‘shadow’ could form northwest of Lake Okeechobee over which significantly less rainfall, and possibly little to none, would occur relative to the surrounding areas. Afternoon rains could extend into the evening with a continued chance of isolated or widely scattered east-coast rains overnight. SE to occasionally S winds 5 to 15 mph but 10 to 20 mph during the afternoon in coastal areas, with occasional gusts up to 25 mph. Winds diminishing to 5 to 10 mph or less over the interior overnight (0.32").

Thursday: Significantly less total rainfall, with total rainfall probably below the daily climatological average. A chance of isolated or widely scattered shower activity in the east during the morning, followed by decreasing rain chances during the afternoon. The widely scattered rains likely over the interior and the west, with the greatest rain stretching from near the west coast through the Kissimmee Valley. A lake ‘shadow’ could form west-northwest or northwest of Lake Okeechobee over which significantly less rainfall, and possibly little to none, would occur relative to the surrounding areas. Afternoon rains diminishing by the early evening, followed by a chance of very isolated east-coast showers overnight. Mainly E to SE winds 5 to 15 mph, except occasionally SE to S north of Lake Okeechobee. Light winds overnight (0.08").

7-Day SFWMD-wide QPF/(Most Likely Range): 1.45" (0.85”-2.20”)

Historical 7-Day Average: 1.74"

Lake Okeechobee Info:

https://w3.saj.usace.army.mil/h2o/reports/r-oke.txt

NWS Hazardous Weather Outlooks:

https:/apps.sfwmd.gov/sfwmd/common/images/weather/hwo_sfwmd.html