Fourthcast: Flash Flood Watch

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Overview

You won’t find any jokes in this fourthcast, because it sucks.

An unusually wet weather pattern is arriving, and it won’t change for the next several days.  This will be like a tropical system, full of moisture and thunderstorm chances. Strong to severe thunderstorms cannot be ruled out at any time over the next several days.

But the main story will be rain.  A lot of rain.

Tonight

Rain will be close by. Weather models keep the rain in East Tennessee, but extend it as far west as I-65. This may be our last dry night for a while.

Fourthcast

Our NWS has issued a Flash Flood Watch effective beginning at 12 a.m. Thursday morning through Friday at 7 p.m.

...HEAVY RAINFALL AND FLASH FLOODING POSSIBLE THROUGH FRIDAY... .A DEEP SOUTHERLY FLOW OF TROPICAL MOISTURE WILL MOVE ACROSS MIDDLE TENNESSEE THROUGH FRIDAY. THE HIGH LEVELS OF MOISTURE COMBINED WITH AN UNUSUALLY STRONG UPPER LEVEL JET STREAM OVER THE REGION WILL PRODUCE WIDESPREAD AND PERSISTENT SHOWERS AND THUNDERSTORMS TONIGHT THROUGH FRIDAY EVENING. WIDESPREAD RAINFALL TOTALS OF 2 TO 4 INCHES ARE EXPECTED...WITH SOME LOCATIONS SEEING UP TO 6 INCHES OF RAIN. read more

Rainy & Cooler Weather Continues: Wet Fourth?

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Rest of Monday – High 84; Scattered Thunderstorms

Thunderstorms have been weaving in and out of the area all afternoon, thanks to a meandering low pressure system that will be hanging around the next few days. Even though most of the storm activity is to our east, there still could be some storms well after sunset. We may also see some patchy fog late tonight. read more

Unsettled Weather, Below Normal Temps Next Several Days

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Next Several Days

A low pressure center at 500 mb (that’s at 18,000 feet) will wander south from the Great Lakes, then spin around through the 4th of July. See the below (patriotic) loop from June 29 through July 7. The low pressure is red.  This will “unsettle” our weather through the 4th.

Our NWS says:

THIS DOESNT MEAN IT IS GOING 
TO RAIN EVERY MINUTE OF EVERY
HOUR BUT THERE WILL BE AN ON-
GOING CHANCE FOR SHOWERS AND 
A FEW THUNDERSTORMS ON A 
DAILY BASIS.

They continue:

EVEN AFTER UPPER LOW LIFTS NORTHWARD INTO CANADA AROUND JULY 4TH WE HAVE SUCH A GOOD MOISTURE FEED FROM THE GULF OF MEXICO INTO THE TENNESSEE VALLEY THANKS TO A RATHER STRONG BERMUDA HIGH KEEPING THE CHANCE OF SHOWERS AND THUNDERSTORMS. read more

Afternoon Update: Details on Tonight’s Wind/Hail/Tornado Risk

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The 3 p.m. update from the Storm Prediction Center was largely unchanged for us. The probabilities of “x” happening within 25 miles of you today:

  • Damaging Winds (58mph+): 30%

  • Large Hail (1″+): 15%

  • Tornado: 2%:

Afternoon thunderstorms (previously advertised as “Round 1”) haven’t developed as predicted by weather models, likely due to a “cap” up in the atmosphere preventing a large amount of thunderstorm energy from being released. Also limiting afternoon thunderstorms has been some “mixing,” causing drier dewpoints to come on down . . . read more