After Making Landfall Over SW Louisiana As A Cat 4 Laura, Now A Tropical Storm, Moves Through the Lower Mississippi Valley

 

000

WTNT43 KNHC 280234

TCDAT3

Tropical Depression Laura Discussion Number  33

NWS National Hurricane Center Miami FL       AL132020

1000 PM CDT Thu Aug 27 2020

Laura has continued to spin down after being over land for nearly a 

day.  Surface observations no longer support tropical storm 

intensity, and therefore the system is being downgraded to a 

tropical depression.  The cyclone should become a post-tropical 

low within a couple of days, and then transform into an 

extratropical cyclone while moving off the U.S. east coast.  The 

official forecast shows some restrengthening in 2-4 days due to 

baroclinic processes.  However, by the end of the forecast period, 

the system should be absorbed by a larger extratropical cyclone to 

the east of the Canadian Maritimes.

Laura continues to move north-northeastward or at about 015/13 kt.  

A turn toward the northeast and east-northeast with increasing 

forward speed is likely while the cyclone becomes embedded in the 

stronger westerly flow.  The official track forecast follows the 

latest dynamical model consensus.

There is a continued threat of flooding from Laura for the next 

couple of days.  This is the last NHC advisory on Laura.  Future 

information on this system, including the rainfall threat, can be 

found in Public Advisories issued by the Weather Prediction Center 

beginning at 4 AM CDT, under AWIPS header TCPAT3, WMO header 

WTNT33 KWNH, and on the web at http://www.wpc.ncep.noaa.gov 

Key Messages:

1. Additional rainfall will continue to lead to flash flooding 

along small streams, urban areas, roadways, and minor to moderate 

river flooding across portions of Louisiana, Mississippi and 

Arkansas.  The heavy rainfall threat and flash and urban flooding 

potential will spread northeastward into the middle-Mississippi, 

lower Ohio and Tennessee Valleys, and Mid-Atlantic States Friday and 

Saturday.

2. A few tornadoes remain possible this evening across eastern 

Arkansas, western Tennessee, northern Mississippi, and the Missouri 

Bootheel. The risk for a few tornadoes is expected to redevelop 

Friday afternoon into the evening across parts of the Mid-South and 

Tennessee Valley regions.

FORECAST POSITIONS AND MAX WINDS

INIT  28/0300Z 35.1N  92.0W   30 KT  35 MPH...INLAND

 12H  28/1200Z 36.3N  91.0W   30 KT  35 MPH...INLAND

 24H  29/0000Z 37.3N  87.8W   25 KT  30 MPH...INLAND

 36H  29/1200Z 38.0N  82.3W   25 KT  30 MPH...POST-TROP/INLAND

 48H  30/0000Z 38.5N  75.5W   25 KT  30 MPH...POST-TROP/EXTRATROP

 60H  30/1200Z 41.5N  67.5W   35 KT  40 MPH...POST-TROP/EXTRATROP

 72H  31/0000Z 44.0N  60.5W   45 KT  50 MPH...POST-TROP/EXTRATROP

 96H  01/0000Z 48.0N  52.0W   40 KT  45 MPH...POST-TROP/EXTRATROP

120H  02/0000Z...DISSIPATE

$$

Forecaster Pasch

000

FXUS61 KCAR 280117

AFDCAR

Area Forecast Discussion

National Weather Service Caribou ME

917 PM EDT Thu Aug 27 2020

.SYNOPSIS...

High pressure will build across the region overnight into

Friday night. Low pressure will cross the region later Saturday

through Sunday. High pressure will build across the region

Monday then exit across the Maritimes Tuesday.

&&.....

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...

A westerly flow aloft can be expected Friday night, as a weak

area of high pressure builds across early. After a mainly clear

start to the evening, warm advection mid/high level cloudiness

will be on the increase later Friday night. Mainly clear skies

and light wind will set the stage for some radiational cooling.

Still appears that the best radiational cooling potential will

be across the far North, where mid 30s and patchy frost is

possible across portions of the North Maine Woods. Elsewhere

across the North, lows will range from the low to mid 40s, with

low 50s across Downeast areas.

On Saturday, the focus turns to an area of low pressure tracking

east from the Great Lakes region. This system will spread rain

toward the region as we head into the day Saturday. There still are

some discrepancies with regard to timing and placement of the

heavier rainfall, and just how much moisture, from what was

once Laura, gets entrained Northward into our area. Stayed

close to previous forecasters POP forecast Saturday/Saturday

Night but loaded most recent WPC QPF forecast. The clouds and

rain, along with NE to E wind will keep high temperatures in the

low to mid 60s regionwide Saturday afternoon.

Low pressure continues to move east to the Canadian Maritimes

Saturday night, Steadier rain will begin to taper to showers across

Downeast areas later Saturday night. Across the North, rain will

likley continue as a trof hangs back across the region behind the

departing low.

Although the steadier rainfall across the North will diminish

early Sunday, the weather will remain unsettled, as an upper

level trof crosses the region. This will keep the chance for

showers, especially across the North on Sunday. Sunday will be

an unseasonably cold day with highs only in the low to mid 60s

North and upper 60s to near 70 Downeast.

&&.......

ZCZC MIATCUAT3 ALL

TTAA00 KNHC DDHHMM

 

Hurricane Laura Tropical Cyclone Update

NWS National Hurricane Center Miami FL       AL132020

200 AM CDT Thu Aug 27 2020

...EYEWALL OF LAURA PUSHING INLAND ACROSS SOUTHWESTERN LOUISIANA...

...CATASTROPHIC STORM SURGE, EXTREME WINDS, AND FLASH FLOODING

ONGOING...

The eyewall of Laura will continue to move inland across 

southwestern Louisiana during the next several hours. TAKE COVER 

NOW! Treat these imminent extreme winds as if a tornado was 

approaching and move immediately to the safe room in your shelter. 

Take action now to protect your life!

The safest place to be during a major landfalling hurricane is in a 

reinforced interior room away from windows. Get under a table or 

other piece of sturdy furniture. Use mattresses, blankets or pillows 

to cover your head and body. Remain in place through the passage of 

these life-threatening conditions.

A National Ocean Service tide station at Calcasieu Pass, Louisiana 

observed a water level rise of 9.19 ft Mean Higher High Water 

at 100 CDT.

The Lake Charles, Louisiana airport recently reported a sustained 

wind of 85 mph (137 km/h) with a gust to 128 mph (206 km/h).

A University of Florida observing tower near Lake Charles recently 

reported a sustained wind of 86 mph (138 km/h) with a gust to 112 

mph (180 km/h)

A Texas Coastal Ocean Observing Network site at Sabine Pass on the 

Texas/Louisiana border recently reported sustained winds of 74 mph 

(119 km/h) with a gust to 90 mph (145 km/h).

SUMMARY OF 200 AM CDT...0700 UTC...INFORMATION

-----------------------------------------------

LOCATION...30.0N 93.3W

ABOUT 10 MI...15 KM SW OF LAKE CHARLES LOUISIANA

ABOUT 40 MI...65 KM E OF PORT ARTHUR TEXAS

MAXIMUM SUSTAINED WINDS...140 MPH...225 KM/H

PRESENT MOVEMENT...N OR 350 DEGREES AT 15 MPH...24 KM/H

MINIMUM CENTRAL PRESSURE...941 MB...27.79 INCHES

 

$$

Forecaster Zelinsky/Cangialosi/Blake

NNNN