Home Storm Tracker TROPICAL STORM NICHOLAS FORECAST SYNOPSIS…ISSUED SEP. 13, 2021…12:20 P.M. EDT

TROPICAL STORM NICHOLAS FORECAST SYNOPSIS…ISSUED SEP. 13, 2021…12:20 P.M. EDT

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TROPICAL STORM NICHOLAS FORECAST SYNOPSIS…ISSUED SEP. 13, 2021…12:20 P.M. EDT


Disclaimer:  This site is not affiliated with the National Hurricane Center, Hurricane Hunters, Storm Prediction Center, or National Weather Service.  ALL forecasts herein are the result of my analysis, and I am solely responsible for the content.  As ALWAYS, follow the National Hurricane Center, National Weather Service, and your local Emergency Management officials for emergency decisions.  In addition, this is strictly a FORECAST OFFICE.  I CANNOT make decisions regarding travel plans, etc.  My purpose, is to provide you the information, based solely on information I analyze, and the accuracy of the information at hand of the time of analysis, so you may make informed decisions.
(T. F. “Storm” Walsh)

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Please be aware, even though I do not post every night, rest assured I am continuously monitoring various areas for any significant weather.  I will be taking Sundays off (family time), unless we have active systems that may be posing a threat (i.e. Tropical, Winter Weather, Coastal Storms, etc.).
STORM WALSH PRE-SEASON FORECAST
TOTAL NAMED STORMS: 17 – 20
TOTAL HURRICANES :        7 – 9
MAJOR HURRICANES:       4 – 5

AVERAGE HURRICANE SEASON:
TOTAL NAMED STORMS: 14
TOTAL HURRICANES:         7
MAJOR HURRICANES:       3

2021 SEASON TOTALS:
TOTAL NAMED STORMS:  14
TOTAL HURRICANES:          5
MAJOR HURRICANES:        3

TOTAL U. S. LANDFALLS:    6

The following is the list of storm names for the 2021 Atlantic Hurricane Season:
Ana Bill Claudette Danny Elsa Fred Grace Henri Ida Julian Kate Larry
Mindy Nicholas Odette Peter Rose Sam Teresa Victor Wanda
As a storm becomes named, I will be marking it in bold red to keep track of the activity for this Atlantic season.

Please note..when we are dealing with multiple systems, they will be listed in order as to the greatest threat to land or the U. S. , to the least threat.

Good day everyone,
I’ve decided to print everything in bold for easier reading.  Please let me know if you prefer this, or if you like the previous print.

The following are satellite animations of the Atlantic Basin and Africa
ATLANTIC BASIN
48882110ATL
AFRICA
sat_20210913_1400_animation
Ok gang, the main focus this morning will be Tropical Storm NICHOLAS.  As of the 11:00 a.m. EDT advisory from the NHC, the following information was available:
10:00 AM CDT Mon Sep 13
Location: 26.4°N 96.8°W
Moving: N at 12 mph
Min pressure: 1002 mb / 29.60 in
Max sustained: 60 mph

Satellite animations show a better defined system this morning.
NICHOLAS IR AND VISIBLE SATELLITE ANIMATIONS
18923064NICHOLASIR
18923064
Based on satellite imagery, and Doppler radar, it appears NICHOLAS is trying to build a new core, in a steady fashion.

The current motion was reported to now be toward the north, however with the new center reformation, NHC indicates a little uncertainty.  Based on current and short term forecast steering layers, NICHOLAS appears to now be heading for the weakness in the ridge.
850 – 500 MB STEERING LAYER
gfs_uv_500_850_gulf_6
Based on analysis of forecast steering, and recent model guidance, albeit I am expecting on the update, a slight shift right in track will be in order, I agree with the NHC froecast track, and based on this (wish I could give a narrower range), I believe NICHOLAS will make landfall between Port Lavaca, and Freeport Texas sometime early tomorrow morning.
ATCF 12Z GUIDANCE
atcf-nicholas14l-1631534400-1534400
NHC SPAGHETTI PLOT
AL14_current
ECMWF EPS AND GEFS
AL14_2021091306_ECENS_0-120h_large
AL14_2021091306_GEFS_0-120h_large
NHC TRACKING MAP (LINKED TO INTERACTIVE MAP)
143722_5day_cone_no_line_and_wind

As stated, NICHOLAS has improved in structure, and maximum sustained winds reported by Hurricane Hunter aircraft were 60 mph.  Central pressure has dropped since the earlier reading of 1005 mb.  This is a little perplexing in that he looks so good, as the recent wind shear map indicates NICHOLAS is still under some shear.  However, NICHOLAS is displaying some excellent outflow from the north, and around the eastern semi-circle.  I haven’t researched how this works yet, however based on the combination of the upper level outflow, extremely warm SST’s and moderate to high OHC, these factors may be overcoming the shear somewhat.  In fact, just reading the NHC previous discussion, pretty much the same thing is mentioned.  Looking at satellite images however, NICHOLAS does not appear to be a sheared system.  This is most likely due to the fact the shear vector is almost in line with the track / motion of the storm, thereby negating most of the magnitude of the shear.  Based on analysis of forecast wind shear and the 200 mb pattern, shear may improve slightly (slight weakening based on current shear tendency) during the next 6 – 12 hours, although if conditions remain the same, NICHOLAS should still continue to strengthen up until landfall.
CIMSS WIND SHEAR AND UPPER LEVEL WIND MAPS
94L.SHEAR
94L.UPPER
ECMWF AND GFS WIND SHEAR FORECAST
ecmwf-deterministic-gulf-shear_850v200-1545200
gfs_dl_shear_gulf_6
ECMWF 200 MB FORECAST
ecmwf-deterministic-gulf-z200_speed-1523600
Ample moisture is still forecast from the surface up to the 500 mb up until landfall, along with SST’s of 30 C and OHC values of around 45 – 60 kj/cm-2.  Based on this analysis, and given how quickly NICHOLAS has improved in satellite presentation from very early morning, I’m expecting NICHOLAS to continue strengthening.  I agree with the NHC intensity forecast at the moment, however the slight shift in the center could allow for just slightly enough more time over water, and I cannot rule out NICHOLAS becoming a Category 1 hurricane just near landfall.  Given what we have witnessed from 2 other hurricanes that intensified quickly prior to landfall, this may occur in NICHOLAS, about 6 hours prior.  This is not uncommon for being in phase 3 of the MJO.

Residents within the Hurricane Watch area should be completing preparations as quickly and safely as possible!
NHC INTENSITY FORECAST

INIT  13/1500Z 26.4N  96.8W   50 KT  60 MPH
 12H  14/0000Z 27.5N  96.7W   60 KT  70 MPH
 24H  14/1200Z 29.1N  96.3W   45 KT  50 MPH...INLAND
 36H  15/0000Z 30.2N  95.4W   30 KT  35 MPH...INLAND
 48H  15/1200Z 31.0N  94.0W   25 KT  30 MPH...INLAND
 60H  16/0000Z 31.5N  92.5W   20 KT  25 MPH...INLAND
 72H  16/1200Z 32.0N  91.1W   20 KT  25 MPH...POST-TROP/REMNT LOW
 96H  17/1200Z...DISSIPATED

NHC PUBLIC ADVISORY

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Storm Surge Warning is in effect for...
* Port Aransas Texas to Sabine Pass
* Galveston Bay, Aransas Bay, San Antonio Bay, and Matagorda Bay

A Hurricane Watch is in effect for...
* Port Aransas to San Luis Pass Texas

A Tropical Storm Warning is in effect for...
* Mouth of the Rio Grande to Sabine Pass

A Storm Surge Watch is in effect for...
* Baffin Bay to Port Aransas Texas
* Sabine Pass to Rutherford Beach Louisiana
* Corpus Christi Bay

A Storm Surge Warning means there is a danger of life-threatening
inundation, from rising water moving inland from the coastline,
during the next 36 hours in the indicated locations. For a
depiction of areas at risk, please see the National Weather
Service Storm Surge Watch/Warning Graphic, available at
hurricanes.gov.  This is a life-threatening situation.  Persons
located within these areas should take all necessary actions to
protect life and property from rising water and the potential for
other dangerous conditions.  Promptly follow evacuation and other
instructions from local officials.

A Tropical Storm Warning means that tropical storm conditions are
expected somewhere within the warning area.

A Storm Surge Watch means there is a possibility of life-threatening
inundation, from rising water moving inland from the coastline, in
the indicated locations during the next 48 hours. For a depiction of
areas at risk, please see the National Weather Service Storm Surge
Watch/Warning Graphic, available at hurricanes.gov.

A Hurricane Watch means that hurricane conditions are possible
within the watch area.

Interests elsewhere in southwestern Louisiana should monitor the
progress of Nicholas.

For storm information specific to your area in the United
States, including possible inland watches and warnings, please
monitor products issued by your local National Weather Service
forecast office. For storm information specific to your area
outside of the United States, please monitor products issued by
your national meteorological service.
HAZARDS AFFECTING LAND

Key messages for Nicholas can be found in the Tropical Cyclone
Discussion under AWIPS header MIATCDAT4, WMO header WTNT44 KNHC
and on the web at hurricanes.gov/graphics_at4.shtml?key_messages

RAINFALL:  Nicholas is expected to produce storm total rainfall of 
8 to 16 inches, with isolated maximum amounts of 20 inches, across 
portions of the middle and upper Texas coastal areas through the 
middle of the week. Life-threatening, flash and urban flooding 
impacts are possible, especially across portions of the upper Texas 
Gulf Coast near Lake Jackson and Freeport, TX

Across the rest of southeast Texas into southwest Louisiana rainfall 
of 5 to 10 inches is expected. This rainfall may produce areas of 
considerable flash and urban flooding, especially in highly 
urbanized metropolitan areas. Additionally, there is the potential 
for isolated minor to moderate river flooding.

STORM SURGE:  The combination of a dangerous storm surge and the 
tide will cause normally dry areas near the coast to be flooded by 
rising waters moving inland from the shoreline.  The water could 
reach the following heights above ground somewhere in the indicated 
areas if the peak surge occurs at the time of high tide...

Port O'Connor to San Luis Pass TX including Matagorda Bay...3-5 ft
San Luis Pass, TX to Rutherford Beach, LA including Galveston
Bay...2-4 ft
Baffin Bay to Port O'Connor, TX...2-4 ft
Corpus Christi Bay, Aransas Bay and San Antonio Bay...2-4 ft
Mouth of the Rio Grande to Baffin Bay...1-3 ft
Rutherford Beach, LA to Intracoastal City, LA...1-3 ft
Sabine Lake and Calcasieu Lake...1-3 ft

The deepest water will occur along the immediate coast in areas
of onshore winds, where the surge will be accompanied by large and
dangerous waves.  Surge-related flooding depends on the relative
timing of the surge and the tidal cycle, and can vary greatly over
short distances.  For information specific to your area, please see
products issued by your local National Weather Service forecast
office.

WIND:  Tropical storm conditions are expected within the warning 
area in southern Texas through the next few hours. These conditions 
will spread northward within the warning area through tonight, 
making outside preparations difficult or dangerous. Hurricane 
conditions are possible in the Hurricane Watch area as early as this 
afternoon or this evening. 

TORNADOES:  A couple of tornadoes are possible this afternoon and 
tonight across the middle and upper Texas coast.

SURF:  Swells generated by Nicholas will continue affecting
portions of the northwest Gulf coast through Tuesday. These swells
are likely to cause life-threatening surf and rip current
conditions.  Please consult products from your local weather office.

The following link is for local NWS products regarding NICHOLAS
https://www.nhc.noaa.gov/text/refresh/index_hls4+shtml/122122.shtml?

The following is the experimental storm surge product from the NHC.  The graphics that follow the NHC graphic, is from the SLOSH Software program.  Surge values indicated are plus or minus 20% for a CAT 1 Hurricane.  For example, a strong CAT 1, you would add 20% of the given value.  For a low end, minus 20%
The first is for NICHOLAS moving at 5 mph, the second at 15 mph.
EXPERIMENTAL SURGE
143722_peak_surge
SLOSH SURGE VALUES
NICHOLAS.displayCAT1high
NICHOLAS.displayCAT1.15MPHhigh
143722_key_messages_sm
143722_spanish_key_messages_sm
FORECAST RAINFALL TOTALS
143722WPCQPF_sm
p168i

The following map will allow to to get information from your NWS office.
NWS WATCH / WARNING DISPLAY (LINKED…CLICK MAP, THEN YOUR AREA)

WSI DOPPLER RADAR LOOP (LINKED, CLICK RADAR MAP)

RAP RADAR (CLICK IMAGE THEN RADAR SITE)

COD RADAR (LINKED FOR ANIMATION CONTROLS)
COD-GOES-East-subregional-W_Gulf_Coast.radar.20210913.135000.gif-over=map-bars=

I will continue to monitor NICHOLAS closely over the next 12 hours, for any significant changes in the forecast.

You may direct any questions by contacting me personally, ANYTIME, at: [email protected]

Have a blessed day!

T. F. “STORM” WALSH III
GMCS, USCG (ret)
METEOROLOGIST / HURRICANE SPECIALIST /SEVERE WEATHER SPECIALIST
MEMBER WEST CENTRAL FLORIDA AMS

 



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