Dothan Area Weather Discussion Mar 24

Mesoscale Update...

With Our 00 Utc Sounding At Tae Showing Such A Strong Saturated Inversion Between 987 And 968 Mb With Both Temps And Dewpoints Rising From 59 To 64 Degrees, It Was Becoming Very Difficult To Discern Whether We Would Be Able To Break Through The Inversion To Mix The Instability Down To The Sfc If And When The Expected Squall Line Developed And Approached From The West.

In Fact, This Temperature Inversion Continued Up To 67 Degrees At 925 Mb (Though Not Saturated With A Dewpoint Of 61). Therefore, With So Much Uncertainty, And Still A Solid Severe Weather Potential
Indicated In The Hi-Res Models (Combined With The Very Steep
Mid-Level Lapse Rates), We Coordinated With Spc And Ncep To Launch A 06 Utc Special Sounding.

Based On Some Of The Preliminary Data, We Have Made Quite A Bit Of Progress In Eroding This Inversion. It Is Still Present Between The Sfc And 946 Mb, But Is Now Only 3 Degrees (64 T And Td At The Sfc To 67 At The Top Of The Inversion. With It Quickly Eroding Above That Level, Chances Now Appear Quite Good That The Strong Instability Will Indeed Mix Down To The Sfc Out Ahead Of The Squall Line. In Fact, As Of 200 Am Edt, The Initial Parcel From Our Sounding Launch Point Has Already Reached T=67, Td=67, And Both Continue To Rise At Steady Rate As The Sfc Low Off To Our West Continues To Deepen.

With The 06 Utc Tae Sounding Now Complete, Modified The Sfc Parcel To The Expected High Of T=85, Td=68, To Get A Pwat= 1.54", An Li=-7.4, A Cape= 2577 J/Kg, A Wet Bulb Zero Height Of 10819 Ft Below A Fzl Of 14019 Ft, And A Whopping 627 M^2/S^2 0-3 Km Helicity! If These And Other Significant Severe Weather Parameters In This Sounding Are Reached Or Approached With The Squall Line Or Any Discrete Supercells, All Modes Of Severe Weather Will Clearly Be
Possible!

Near Term [Today]...

Severe Storms Are Expected To Develop Later This Morning With The
Severe Threat Initially Over The Fl Panhandle Zones Shifting To Our
Fl Big Bend And Ga Zones After Sunrise.

As Mentioned Above, We Do Expect Storms Will Get Rooted In The Boundary Layer. Mid Level Lapse Rates Will Steepen To About 7.5 Deg/Km. Shear Will Also Increase With 0-6 Km Bulk Shear Increasing To 55-60 Kt And Cape Surging To 1500-2000 J/Kg.

All Modes Of Severe Weather Will Be Possible With This Round Of Convection, Including Hail, Severe Wind Gusts And Tornadoes. Local Confidence Grids Had Severe Probs Up Around 20% With Tornado Probs At 5%. These Are Both Impressive.

We Expect The Convection To Push East Of The Area By Around 18z.

However, The Cold Front Will Trail Behind Enough To Allow Temps To Soar Into The Mid 80s. This Should Be The Warmest Day We Have Seen Since November 3.

It Will Also Be A Breezy Afternoon With Frequent Gusts Up Around 30
Mph.

Short Term [Tonight Through Tuesday]...

Upper Trough Over Ern Conus Will Gradually Deamplify And Move Ewd Thru The Period. Assocd H5 Low Will Move From Wv Ewd Into Atlc By Sunrise Monday. This Will Leave A Very Tight Nearly Zonal Flow
Over Se Region. At Surface, Low Invcnty Of Mid-Atlc Coast At 12z
Mon Will Exit The Coast Early Mon.

In Its Wake, A Large Ridge With An Unseasonably Cold/Dry Dome Of High Pressure Will Move From The Plains Towards The Ms River Valley On Monday And Approach Local Region On Tuesday.

So, In The Wake Of Cold Front A Much Cooler And Drier Airmass Will Filter In. Expect Breezy And Gusty Conditions Thru The Period.

With Clearing Skies, Temps Sun Night Will Drop To Around 40 Se Al To Near 50 Se Big Bend.

Despite Full Sunshine, Mondays Highs Will Be About 20 Degrees Cooler Than Sundays, Near 60 Se Al To Mid 60s Se Big Bend.

Under Increasing Cold Air Advection, Min Temps Monday Night Will Drop Into The Mid 30s.

Highs On Tuesday Drop To The Upper 50s Se Al To Low 60s Se Big Bend.

Long Term [Tuesday Night Through Friday]...

The Extended Period Will Be Dry With Below Seasonal Temperatures
Through Thursday Night.

High Temperatures Will Range From The Upper 50s Northern Zones To Lower 60s Across North Florida On Wednesday.

Max Temps Moderate To The Mid To Upper 60s Thursday And Around 70 To The Lower 70s On Friday.

A Widespread Light Freeze Is Possible Tuesday Night.

Min Temps Will Be In The Mid To Upper 30s Wednesday Night And Then Around 40 Thursday Night.

Aviation...Through 06z Monday…

Lifr To Vlifr Conditions Will Continue This Morning North Of The Warm Front With Intermittent Light Showers In The Warm Advection Regime.

Convection Is Expected To Fire After 09z And Some Of The Storms Will Be Severe.

The Best Window For Thunderstorms At The Taf Sites Is 10-16z. During That Time, Ceilings Could Improve To Mvfr.

After The Convection Ends, The Primary Impact Will Be Westerly Winds That Will Frequently Gust To Around 25 Knots.

Skies Will Clear In The Evening, But Winds Will Remain Gusty As They Veer To The Northwest.

Marine...

Dense Fog Expected Overnight Early This Morning Especially Ern
Waters.

Onshore Flow Will Increase Through Today Along An Approaching Squall Line And Parent Cold Front.

Small Craft Advisory Winds And Seas Are Expected.

Strong Offshore Flow Will Develop Later Today From W-E In The Wake Of A Cold Front With Advisory Conditions Persisting At Least Across The Offshore Segments Through Monday Evening Before Subsiding.

Fire Weather...

Drier Air Will Arrive Behind A Cold Front With Minimum Rh Of 20-25%
On Monday.

Winds Will Also Remain Elevated And It Appears Likely That Our Southeast Al Zones Will Meet Their Red Flag Criteria. A Watch Will Be Issued.

It Will Be Nearly As Dry On Tuesday, But Winds Will Be Lower And Red Flag Criteria Are Unlikely To Be Met On That Day.

Hydrology...

Latest Radar Estimates And Local Obs Show That Widespread 2 To 3
Inches Have Fallen South Of I-10 In N Fl And Adjacent Ga With
Lesser Amounts Elsewhere Across The Local Area.

An Additional 1 To 2 Inches Is Possible Thru Sunday Morning If Squall Sets Up Just Right.

Because This Event Is Expected To Be Of Relatively Short Duration (About 24 Hours) And Current Rather High Flash Flood Guidance, Widespread Flooding Is Not Anticipated With This System.

However, Localized Flooding In The Usual Flood Prone Areas Is
Possible.

Additionally, Widespread Rainfall Of This Amount Will Likely Push
Several Area Rivers Back To Action Stage With A Few Of The Faster
Responding Basins Potentially Reaching Minor Flood Stage By Early
Next Week. This Includes The Sopchoppy River 13.98 Feet Forecast To Rise To 25.97 Feet At 1am Mon. Two Rivers Are Forecast To Rise To Minor Flooding Stage. They Are The Aucilla At Lamont, 8.23 Feet
Forecast To Rise To 10 Feet At 1am Tues, And The Withlacoochee River At Valdosta, 9.36 Feet Forecast To Rise To 13.7 Feet At 1 Am Mon.

Preliminary Point Temps/Pops...

Tallahassee 85 43 64 35 62 / 70 10 0 0 10
Panama City 77 47 65 41 59 / 50 10 0 0 10
Dothan 80 41 61 34 59 / 50 10 0 0 10
Albany 81 42 61 33 58 / 70 10 0 0 10
Valdosta 82 45 63 34 61 / 80 10 0 0 10
Cross City 80 49 64 36 63 / 80 10 0 0 10
Apalachicola 78 48 64 43 59 / 60 10 0 0 10

Tae Watches/Warnings/Advisories...

Fl...
High Rip Current Risk Walton...Bay And Western Gulf Counties
Through Early Monday.

Ga...
None.

Al...
Fire Weather Watch From Monday Afternoon Through Monday
Evening For Coffee-Dale-Geneva-Henry-Houston.

Gm...
Dense Fog Advisory Until 10 Am Edt This Morning For The
Eastern Waters.

Small Craft Advisory Until 8 Pm Edt Monday For All Waters.


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