Tropical Unrest.

A few weeks ago we were basking in relative calm.   Even those systems would steer away into the Central Atlantic.  Those in the area of the Yucatan Peninsula and into Mexico.   But something was afoot,   I sensed a problem when the system slowed and gathered moisture and dumped tons of rain.

This was the perfect storm.   Harvey began to ramp up.  I referenced this slowing and the dangers, in so many words.   I did not expect what happened.   It was NOT climate change.   It was an anomaly and weather is about changes.  It’s highs and lows, tightening  pressure gradients and a myriad of other things.

As a consequence of what had happened, thousands were displaced and hungry,  exposed and afraid.  Let’s not criticise people who are doing the best they can.

Going forward,  there are new challenges and new storm systems.  This evening here in North Carolina, we are experiencing lower  clouds before the rain.    There is a quasi-stationary front (warm sector) which will keep the temperatures rather uniform, with overnight lows 68-70.

Hazardous Weather Outlook

Hazardous Weather Outlook
National Weather Service Raleigh NC
448 PM EDT Thu Aug 31 2017

NCZ007>011-021>028-038>043-073>078-083>086-088-089-010930-
Person-Granville-Vance-Warren-Halifax-Forsyth-Guilford-Alamance-
Orange-Durham-Franklin-Nash-Edgecombe-Davidson-Randolph-Chatham-Wake-
Johnston-Wilson-Stanly-Montgomery-Moore-Lee-Harnett-Wayne-Anson-
Richmond-Scotland-Hoke-Cumberland-Sampson-
448 PM EDT Thu Aug 31 2017

This Hazardous Weather Outlook is for central North Carolina.

.DAY ONE...Tonight.

Hazardous weather is not expected at this time.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday.

Severe thunderstorms will be possible along and south of southward
drifting cold front Friday afternoon and into Friday night. There is
a good chance for severe thunderstorms, capable of producing
tornadoes as well as damaging wind gusts. In addition, locally heavy
rain is expected which may lead to flash flooding, especially in poor
drainage areas.

US (5)

southmissvly_loop

Hazardous Weather Outlook

Hazardous Weather Outlook
National Weather Service Birmingham AL
1101 AM CDT Thu Aug 31 2017

ALZ011>015-017>050-011915-
Marion-Lamar-Fayette-Winston-Walker-Blount-Etowah-Calhoun-Cherokee-
Cleburne-Pickens-Tuscaloosa-Jefferson-Shelby-St. Clair-Talladega-
Clay-Randolph-Sumter-Greene-Hale-Perry-Bibb-Chilton-Coosa-Tallapoosa-
Chambers-Marengo-Dallas-Autauga-Lowndes-Elmore-Montgomery-Macon-
Bullock-Lee-Russell-Pike-Barbour-
1101 AM CDT Thu Aug 31 2017

This Hazardous Weather Outlook is for the counties served by the
National Weather Service office in Birmingham.

.DAY ONE...Outlook through Tonight.

The remnants of Harvey will approach Alabama and is expected to
bring a threat for brief tornadoes to the forecast area. The threat
could continue until 10 PM. The best chance for brief tornadoes
should generally be along and northwest of a line from Selma to
Clanton to Wedowee, though a brief tornado cannot be ruled out
farther south and east.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Activation of storm spotters and emergency management may be needed
through tonight.

$$



 

Wind Advisory

URGENT - WEATHER MESSAGE
National Weather Service Birmingham AL
249 PM CDT Thu Aug 31 2017

...Gusty Winds Possible Across North Central Alabama...

ALZ011>015-017>020-024-026-011100-
/O.NEW.KBMX.WI.Y.0007.170831T1949Z-170901T2100Z/
Marion-Lamar-Fayette-Winston-Walker-Blount-Etowah-Calhoun-
Cherokee-Jefferson-St. Clair-
Including the cities of Hamilton, Sulligent, Vernon, Fayette,
Double Springs, Jasper, Oneonta, Gadsden, Anniston, Centre,
Birmingham, Hoover, Pell City, and Moody
249 PM CDT Thu Aug 31 2017

...WIND ADVISORY IN EFFECT UNTIL 4 PM CDT FRIDAY...

The National Weather Service in Birmingham has issued a Wind
Advisory, which is in effect until 4 PM CDT Friday.

* TIMING...will continue through Friday afternoon.

* WINDS...will be between 15 and 25 mph with gusts up to 35 mph.

* IMPACTS...of the strong winds may break small limbs and cause
  hazardous driving conditions.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Wind Advisory means that wind gusts of 35 mph are expected.
Winds this strong can make driving difficult...especially for
high profile vehicles. Use extra caution.

&&

$$



 

Tornado Watch

TORNADO WATCH OUTLINE UPDATE FOR WT 476
NWS STORM PREDICTION CENTER NORMAN OK
1115 AM CDT THU AUG 31 2017

TORNADO WATCH 476 IS IN EFFECT UNTIL 800 PM CDT FOR THE
 FOLLOWING LOCATIONS

ALC007-009-021-033-043-047-057-059-063-065-073-075-077-079-083-
091-093-103-105-107-117-119-125-127-133-010100-
/O.NEW.KWNS.TO.A.0476.170831T1615Z-170901T0100Z/

AL
.    ALABAMA COUNTIES INCLUDED ARE

BIBB                 BLOUNT              CHILTON
COLBERT              CULLMAN             DALLAS
FAYETTE              FRANKLIN            GREENE
HALE                 JEFFERSON           LAMAR
LAUDERDALE           LAWRENCE            LIMESTONE
MARENGO              MARION              MORGAN
PERRY                PICKENS             SHELBY
SUMTER               TUSCALOOSA          WALKER
WINSTON

Birmingham, Birmingham International Airport 16:53 Overcast 81 71 72 SE 10 29.83
Anniston Metro Airport 16:53 Mostly Cloudy 84 71 65 SE 9 G 20 29.88
Atlanta, Hartsfield – Jackson Atlanta International Airport 16:52 Partly Cloudy 82 67 60 SE 5 29.96
Auburn-Opelika Airport 16:56 Mostly Cloudy 82 73 74 S 15 G 21 29.94
Nashville, Nashville International Airport 16:53 Overcast 77 73 88 NE 9 29.87
Alabaster, Shelby County Airport 16:53 Mostly Cloudy 84 72 67 S 17 G 23 29.82
Huntsville, Huntsville International / Jones Field 16:53 Overcast 82 74 77 SE 13 G 24 29.81
Jackson, Jackson International Airport 16:54 Light Rain Fog/Mist 74 72 94 SW 15 G 26 29.75
Memphis International Airport 16:54 Heavy Rain Fog/Mist and Windy 69 66 90 NE 28 G 44 29.67
Montgomery, Dannelly Field 16:53 Partly Cloudy 88 72 59 S 10 G 22 29.86
Tuscaloosa Regional Airport 16:53 Fair 83 76 79 S 13 G 24 29.
Area Forecast Discussion
National Weather Service Birmingham AL
317 PM CDT Thu Aug 31 2017

.SHORT TERM...

The post-tropical center of Harvey is now analyzed south of Tunica,
MS. A synoptic scale warm front was located via surface pressure
field analysis from the surface low center east to just south of
Tupelo, MS. Across the state of Mississippi, surface winds generally
shift across this front but as this feature extends into Alabama, it
is primarily defined by a pressure trough with little in the way of
a wind shift or change in the thermodynamic environment.

Sounding data along with upper air guidance suggests drier air aloft
is present in greater magnitude to the east and the north while
profiles are more moist to the south and the west.

Rotating storms remain likely across our south-central, southwest
and western counties with a limited tornado risk. While
conditions had become somewhat calmer in the short- term,
additional development across our south and west counties continue
to be monitored closely. Tornadoes remain possible as we remain
in the synoptically favored right front quadrant of a former
tropical cyclone.

Breaks in cloud cover continue across our eastern, southeast and
south-central counties and solar insolation continues to result in
surface heating that is increasing instability values. Wind shear is
most prominent off the surface at this time, supporting broad storm
rotation. Wind shear values will increase across our western and
northwest counties for the remainder of this afternoon and evening
as the remnants of Harvey move into western Tennessee.

Radar imagery indicates storms that we are closely watching in
Pickens, Perry and Marengo Counties with more activity to the
southwest. Our southwest and west-central counties continue to have
the greatest potential for rotating storms and possible tornadoes.

JH/05

.LONG TERM...

Rain chances will drop significantly for Friday as much drier air
aloft moves into the region around the southern periphery of
Harvey`s remnant low. The weekend looks dry for most if not all
of our forecast area with the arrival of northwesterly flow. The
next chance of rain may not come until Tuesday as southerly flow
develops in advance of an approaching upper-level trough.

&&

.AVIATION...
18Z TAF Discussion.

Band one has exited the TAF window to the east and now watching
band 2 begin to work in from the west. Looks to move into TCL at
or just past 18Z and then work into EET and BHM by 20 to 21Z and
then sliding northeastward after that. There should be a line that
moves through MGM and TOI as well, but they may not see the amount
of activity as the northern sites. As the center of the remnants
of Harvey moves northeast, we will see low clouds and showers
overnight at the northern sites along with the main low itself.

Note: Have put in AMD NOT SKED for KASN TAF since winds are
missing from the observation and will be a factor in the forecast
today and tonight.

16

&&

.FIRE WEATHER...

High rain chances are expected through tonight with tropical
moisture in place. A drying trend will follow for Friday and the
weekend. There are no fire weather concerns at this time.

&&

.PRELIMINARY POINT TEMPS/POPS...
Gadsden     69  80  60  81  60 /  90  50  20  10  10
Anniston    70  82  63  83  62 /  90  40  20  10  10
Birmingham  70  82  64  83  64 /  90  30  20  10  10
Tuscaloosa  70  84  66  86  64 /  90  20  10  10   0
Calera      70  82  65  85  65 /  90  20  10  10  10
Auburn      71  84  66  84  65 /  70  30  20  10  10
Montgomery  73  88  67  88  67 /  70  20  10  10  10
Troy        72  87  68  87  66 /  40  20  10  20  10

&&

.BMX WATCHES/WARNINGS/ADVISORIES/...
Wind Advisory until 4 PM CDT Friday for the following counties:
Blount...Calhoun...Cherokee...Etowah...Fayette...Jefferson...
Lamar...Marion...St. Clair...Walker...Winston.

&&

mcd1605

 

Mesoscale Discussion 1605
NWS Storm Prediction Center Norman OK
1031 AM CDT Thu Aug 31 2017

Areas affected…Parts of eastern Mississippi into western Alabama

Concerning…Severe potential…Watch possible

Valid 311531Z – 311730Z

Probability of Watch Issuance…60 percent

SUMMARY…Some increase in the risk for generally isolated and
relatively short-lived tornadoes may occur through midday and early
afternoon. It is not yet certain that a watch will be needed, but
trends are being monitored for this possibility.

DISCUSSION…East of the remnant circulation center of Harvey,
tropical boundary layer moisture (mid 70s+ F surface dew points)
remains present in a narrow corridor roughly centered near the
Mississippi/Alabama state border area. Breaks in cloud cover across
this region have allowed for some insolation and destabilization, as
a broken band of convection pivots across the region. Coinciding
with a broad belt of 30-50 kt southerly 850 mb flow, which is
contributing to sizable low-level hodographs where near surface flow
remains southeasterly (mainly ahead of the broken band of
convection), at least some risk for brief tornadoes remains evident.
However, the extent of this threat remains unclear, and will
probably hinge on whether rain cooled air now present across much of
central and southern Alabama can modify appreciably. Currently this
seems unlikely, but a couple of corridors of substantive further
boundary layer destabilization seem at least possible. One of these
may extend north and east of Biloxi MS into southwestern Alabama
(near/north of Mobile). The other may develop near Tuscaloosa
northwestward into areas near/east of Tupelo and Columbus MS.

..Kerr/Grams.. 08/31/2017

…Please see http://www.spc.noaa.gov for graphic product…

ATTN…WFO…BMX…HUN…MOB…MEG…JAN…LIX…

LAT…LON 30618883 31698838 33188861 33878880 34578878 34878820
33188731 32508771 31978792 31188782 30448833 30368885
30618883

================================================================

http://www.spc.noaa.gov/products/wwa/

enh_0000

 

ww0476_radar

URGENT – IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 476
NWS Storm Prediction Center Norman OK
1115 AM CDT Thu Aug 31 2017

The NWS Storm Prediction Center has issued a

* Tornado Watch for portions of
Northern and western Alabama
Northeast Mississippi
Southwest Tennessee

* Effective this Thursday morning and evening from 1115 AM until
800 PM CDT.

* Primary threats include…
A couple tornadoes possible
Isolated damaging wind gusts to 65 mph possible

SUMMARY…Arcing bands of showers and storms will pose a risk for
brief tornadoes this afternoon into early evening.

The tornado watch area is approximately along and 70 statute miles
either side of a line from 60 miles north of Oxford MS to 55 miles
southeast of Tuscaloosa AL. For a complete depiction of the watch
see the associated watch outline update (WOUS64 KWNS WOU6).

PRECAUTIONARY/PREPAREDNESS ACTIONS…

REMEMBER…A Tornado Watch means conditions are favorable for
tornadoes and severe thunderstorms in and close to the watch
area. Persons in these areas should be on the lookout for
threatening weather conditions and listen for later statements
and possible warnings.

&&

AVIATION…Tornadoes and a few severe thunderstorms with hail
surface and aloft to 0.5 inches. Extreme turbulence and surface wind
gusts to 55 knots. A few cumulonimbi with maximum tops to 450. Mean
storm motion vector 20030.

 

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