Possible Heavy Rain/Flooding Event 12/4-6

[Thundersnow]

Just in from OHX...

NATIONAL WEATHER SERVICE NASHVILLE TN
1204 PM CST THU DEC 1 2011

...HEAVY RAINFALL AND FLOODING POSSIBLE EARLY NEXT WEEK ACROSS
MIDDLE TENNESSEE...

A SLOW MOVING STORM SYSTEM IS EXPECTED TO BE APPROACHING MIDDLE
TENNESSEE BY SUNDAY. AS IT APPROACHES...VERY MOIST AIR WILL
STREAM INTO THE REGION FROM THE SOUTH AND SOUTHWEST.

THE STRONG AND SLOW MOVING STORM SYSTEM WILL COMBINE WITH THE
UNUSUALLY MOIST AIR TO PRODUCE SIGNIFICANT AND WIDESPREAD
RAINFALL SUNDAY THROUGH TUESDAY. RAINFALL AMOUNTS OVER 3 INCHES
WILL BE COMMON...AND SOME AREAS COULD HAVE MORE THAN 5 INCHES.

SINCE MIDDLE TENNESSEE HAS HAD RECENT HEAVY RAINFALL...SOILS ARE
ALREADY MOIST. ANOTHER ROUND OF HEAVY RAINFALL COULD QUICKLY
RESULT IN FLOODING ACROSS THE MID STATE...INCLUDING FLOODING OF
SOME MAJOR RIVERS.

THIS EVENT IS STILL A FEW DAYS IN THE FUTURE...WITH SOME
UNCERTAINTY REGARDING EXACT RAINFALL AMOUNTS. HOWEVER...THE
WEATHER PATTERN LOOKS FAVORABLE FOR HEAVY RAINFALL. EMERGENCY
MANAGERS...MEDIA...AND ALL PEOPLE LIVING IN OR VISITING THE AREA
SHOULD PAY CLOSE ATTENTION TO UPDATED FORECASTS FOR THE
POSSIBILITY OF HEAVY RAINFALL AND FLOODING.

As posted earlier, here is a graphic from the HPC:



I figured we start a new topic for this.

[dwagner88]

Wow. That's a sharp cutoff for the heavy rain. Hope it doesn't shift south/east any. After nearly 6 inches with the ull, we really don't need any more.

[jmundie]

Wow. That's a sharp cutoff for the heavy rain. Hope it doesn't shift south/east any. After nearly 6 inches with the ull, we really don't need any more.

That's just through 7 AM your time Tuesday morning. You can rest assured its sinking slowly southeast.

[Eric]

Received a message from my cousin earlier today...he works in Franklin, and part of his duties is to measure the daily temps and precip for the city of Franklin.  Today the NWS advised him that they are expecting between 5 and 7 inches of rain...and if the models hold, to be prepared for possible widespread flooding.   

[Crockett]

I don't even want to think about what another 5-7" of rain would do here on top of the 7" we received this week and the 4" last week.

I'll be surprised if we don't start seeing some slides on some of the mountainous roads soon. Especially with some hard freezes and quick warm-ups sandwiched between these heavy rains...

[dwagner88]

That's just through 7 AM your time Tuesday morning. You can rest assured its sinking slowly southeast.

Ugh. I didn't think about that.

[StormNine]

Now HPC is showing some 6+ inch amounts across Western and Middle TN.

[harlequin]

From NWS Memphis:

[jmundie]

Received a message from my cousin earlier today...he works in Franklin, and part of his duties is to measure the daily temps and precip for the city of Franklin.  Today the NWS advised him that they are expecting between 5 and 7 inches of rain...and if the models hold, to be prepared for possible widespread flooding.   

Flooding in the summer is one thing... But flooding in cold weather is brutal. Add the threat of hypothermia to the dangers of flooding....

[Charles L.]

This is from a METAR in the Guadalupe Pass in SW TX...this is our system yet to come.

KGDP 021251Z AUTO 05044G110KT 330V090 1/4SM -FZRA FZFG SQ VV001 M03/M04

Gotta love those mountain winds!

[Eric]

This is from a METAR in the Guadalupe Pass in SW TX...this is our system yet to come.
 

Gotta love those mountain winds!

Sheesh....sustained at 44kt, but gust to 110kt...holy kite-flyin' weather, Batman!

[Eric]

Newest HPC qpf map....

[Eric]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NASHVILLE TN
309 AM CST FRI DEC 2 2011

.DISCUSSION...DENSE FREEZING FOG ALREADY SETTING UP AROUND RIVERS
AND LAKES, SO HAVE GONE AHEAD AND ISSUED A FREEZING FOG ADVISORY
THIS MORNING. SURFACE MAP AT 08Z SHOWS RIDGE OF HIGH PRESSURE
ALMOST ON TOP OF MIDDLE TENNESSEE, WITH MOSTLY CLEAR SKIES AND
CALM WIND. NOT MUCH CHANGE IN THE FORECAST REGARDING THE UPCOMING
STORM SYSTEM. GFS IS CONSISTENT IN HANDLING THIS EVENT, WITH COLD
FRONT NOSING INTO THE MID STATE BY 00Z MONDAY AND THE UPPER FLOW
NEARLY PARALLEL TO THE SURFACE FRONT. THIS MEANS LITTLE
PROGRESSION OF THE BOUNDARY OVER THE SUCCEEDING 48 HOURS. THIS, OF
COURSE, TRANSLATES TO SIGNIFICANT RAINFALL SPREAD OVER SEVERAL
PERIODS, WITH QPF OF 2 TO 5 INCHES ANTICIPATED FROM 12Z SUNDAY
UNTIL 12Z TUESDAY. UPPER TROUGH WILL FINALLY SWEEP THIS SYSTEM
THROUGH ON WEDNESDAY, BUT NOT BEFORE TEMPERATURES PLUNGE AND BRING
A CHANCE OF SNOW ON THE BACK END OF THE SYSTEM, ESPECIALLY ON
TUESDAY NIGHT.

 

[jmundie]

I do think this will transition over to snow eventually, but what concerns me most is the low level cold pushing in. I kinda wonder if NE ark, West Tenn might have a freezing rain issue. Models are notoriously bad at handling low level cold air in these situations... with this giant long positive tilted trough, I don't see how we don't end up with cold surface air pushing underneath slow moving precipitation.

[tsmith7101]

Do you think we will see any freezing rain out of this over middle tenn? OHX is saying a low of 36 on Tuesday night but, I am wondering what temps will be in the upper levels.  We will see a warm nose push in to keep us from getting any frozen precip? Its one thing to get 5 inches of rain but it is a completely different scenario to see 5 inches of ice