Severe WX Sunday March 3 Severe Threat

[MattW]

How does the HRRR typically do compared to the 3k NAM?

 

[apocalyptic_pleasures]

If the SPC believes there will be a small cluster of tornadoes, wouldn't this warrant a High risk?

 

[CheeselandSkies]

Not really. High risks are for higher-confidence, large-scale outbreaks. Right now it's really just the HRRR that suggests the possibility, and it oversold last Saturday pretty badly (lots of strong UH tracks through parts of MS and TN that got nothing).

 

[Daryl]

I think there needs to be major changes to the SPC forecast. .

They changed their tune in a hurry.

 

[KoD]

What was the "tell" y'all had a few days ago that made you guess (seemingly correctly) that the warm front wasn't going to advance very far north? Position and weakness of the low?

 

[apocalyptic_pleasures]

Weekend weather lady on channel 4 in Dothan just said expect an enhanced risk with some damaging straight line winds tomorrow with no mention of Tornadoes. Hopefully she's right but clicking your town on the model maps and seeing 'PDS TORNADO' in the hazards spot is never very comforting. Hope they bring the chief weather guy in tomorrow to cover this too.

 

[apocalyptic_pleasures]

New day 1-Larger Enhanced area

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF SOUTHERN/EASTERN AL INTO WESTERN/CENTRAL GA...

..SUMMARY

SCATTERED STRAIGHT-LINE DAMAGING WINDS AND A FEW TORNADOES WILL BE
POSSIBLE TODAY ACROSS PARTS OF THE SOUTHEAST. A COUPLE OF THESE
TORNADOES COULD BE STRONG ACROSS PARTS OF SOUTHERN/EASTERN ALABAMA
INTO WESTERN GEORGIA, MAINLY THIS AFTERNOON.

..SYNOPSIS

A LOW-AMPLITUDE SOUTHERN-STREAM SHORTWAVE TROUGH WILL ADVANCE
QUICKLY EASTWARD ACROSS THE SOUTHERN PLAINS AND SOUTHEAST TODAY. A
SOUTH-SOUTHWESTERLY LOW-LEVEL JET IS FORECAST TO STRENGTHEN TO
AROUND 40-55 KT ACROSS PARTS OF THE SOUTHEAST BY THIS AFTERNOON. A
WEAK SURFACE LOW INITIALLY ALONG THE TX/LA BORDER AT THE START OF
THE PERIOD WILL DEVELOP NORTHEASTWARD TO THE VICINITY OF EASTERN GA
AND SC BY THIS EVENING WHILE GRADUALLY DEEPENING.

..SOUTHEAST

LOW-LEVEL MOISTURE RETURN WILL OCCUR AHEAD OF THE SURFACE LOW FROM
SOUTHERN LA/MS INTO PARTS OF SOUTHERN/CENTRAL AL, NORTHERN FL, GA,
AND SC TODAY. A COLD FRONT ATTENDANT TO THIS LOW WILL SWEEP
SOUTHEASTWARD ACROSS THIS REGION THROUGH THE PERIOD, AND
THUNDERSTORMS ARE EXPECTED TO FORM ALONG THE FRONT BY THIS
AFTERNOON. BOTH LOW- AND MID-LEVEL FLOW WILL STRENGTHEN AS A 50-75
KT MID-LEVEL JET OVERSPREADS THIS REGION. FORECAST EFFECTIVE BULK
SHEAR OF 40-50 KT WILL SUPPORT ORGANIZED UPDRAFTS ACROSS THE WARM
SECTOR. ALTHOUGH LOW AND MID-LEVEL LAPSE RATES WILL LIKELY REMAIN
GENERALLY WEAK, SOME DIURNAL HEATING WILL OCCUR AHEAD OF THE FRONT,
AND INCREASING LOW-LEVEL MOISTURE CHARACTERIZED BY LOW TO MID 60S
DEWPOINTS WILL LIKELY SUPPORT 500-1000 J/KG OF MLCAPE THROUGH PEAK
HEATING. LOCALIZED AREAS ACROSS PARTS OF SOUTHERN/EASTERN AL INTO
WESTERN/CENTRAL GA AND THE FL PANHANDLE MAY HAVE MLCAPE UP TO 1500
J/KG WHERE SURFACE HEATING AND LOW-LEVEL MOISTURE SHOULD BOTH BE
MAXIMIZED.

THE CONVECTION THAT WILL DEVELOP BY EARLY THIS AFTERNOON ALONG/JUST
AHEAD OF THE COLD FRONT WILL LIKELY POSE AN ISOLATED TO SCATTERED
DAMAGING WIND THREAT GIVEN STRONG LOW-LEVEL FLOW JUST OFF THE
SURFACE AND GENERALLY LINEAR MODE. THERE IS A CONDITIONAL THREAT FOR
SUPERCELLS TO DEVELOP ACROSS THE OPEN WARM SECTOR AHEAD OF THE FRONT
PER SOME CONVECTION-ALLOWING MODEL GUIDANCE, MAINLY IN PARTS OF
SOUTHERN/EASTERN AL INTO WESTERN GA THIS AFTERNOON. IF THIS SCENARIO
WERE TO OCCUR, THEN A FEW TORNADOES WOULD BE POSSIBLE GIVEN THE
STRONG SHEAR ASSOCIATED WITH THE PREVIOUSLY MENTIONED LOW-LEVEL JET.
A COUPLE OF THESE TORNADOES COULD BE STRONG WHERE THE GREATEST
INSTABILITY AND SHEAR ARE FORECAST TO OVERLAP, BUT MUCH UNCERTAINTY
REMAINS REGARDING A FAVORABLE SUPERCELL MODE/DEVELOPMENT AHEAD OF
THE FRONT. STORMS WILL LIKELY CONSOLIDATE INTO A BROKEN SQUALL LINE
AND SWEEP EASTWARD ACROSS GA INTO WESTERN SC FROM LATE AFTERNOON
INTO EARLY EVENING, WITH MAINLY A DAMAGING WIND THREAT CONTINUING. A
TORNADO OR TWO WOULD ALSO REMAIN POSSIBLE WITH EMBEDDED CIRCULATIONS
WITHIN THE LINE. EVENTUALLY INSTABILITY IS FORECAST TO DECREASE WITH
EASTWARD EXTENT AS DIURNAL COOLING OCCURS AND THE SURFACE LOW MOVES
OFF THE NC COAST. SOME LINGERING ISOLATED WIND THREAT MAY PERSIST
LATE TONIGHT ACROSS PARTS OF THE COASTAL CAROLINAS.

..GLEASON/KARSTENS.. 03/03/2019

 

[apocalyptic_pleasures]

Whats the significance of some of these storms being shown on the NAM as actually moving ESE rather than the typical NE movement?? I've read on the forums before that a storm sometimes veers to the right as it really intensifies

.

 

[CheeselandSkies]

The way this system is oriented, with the cold front crashing in from the northwest, SE-moving cells should be able to stay ahead of it longer. They might also have better SRH with the forecast SSW surface winds than they would if they were moving NE.

0Z HRRR looks pretty similar to the very ominous 12Z. Puts what looks like a tornadic supercell through the northern FL panhandle into SW GA, through pretty much the same areas that got beat up during Michael.

 

[Jetstream]

 

[TornadoFan]

 

[Taylor Campbell]

I’m in Auburn just waiting right now.

 

[Daryl]

 

[warneagle]

I’m in Auburn just waiting right now.

If you need some lunch recs let me know lol

 

[CAL]

The environment is forecast to be very ripe for right moving supercells in southern Alabama later this afternoon via the latest CAM forecast soundings. Certainly can't say that about many events in the deep south.

 

[warneagle]

That last paragraph of the MD is concerning. No potential weaknesses in the wind fields and no VBV issues.

 

[CAL]

That last paragraph of the MD is concerning. No potential weaknesses in the wind fields and no VBV issues.

Exactly. The deviant supercell storm motion that will likely occur will add fuel to the fire by shifting the storm motion vector off the hodograph and further improving the storm relative wind profile. Concerning for sure.

 

[Bama Ravens]

Just what the northern half of Alabama needs, another mass of heavy rain.

 

[Kory]

Just what the northern half of Alabama needs, another mass of heavy rain.

Yep, areal flood advisories already issued. Still a few more hours of soaking rain left.

 

[Daryl]