June 21, 2021

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SLIGHT SEVERE WEATHER RISK / TROPICAL WEATHER OUTLOOK SYNOPSIS…ISSUED MAY 15, 2021…10:10 A.M. EDT

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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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Good day to everyone!
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.).

The SPC has issued a SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS MUCH OF THE CENTRAL AND SOUTHERN HIGH PLAINS REGION…

…SPC SUMMARY…
Scattered strong/severe thunderstorms are expected across the central/southern High Plains today. Hail and wind are the primary threats.

The SPC DAY 1 Severe Outlook will be linked to the very first SPC graphic, so you may view it in its entirety.
SPC DAY 1 CONVECTIVE OUTLOOK
day1otlk_1200
TORNADO OUTLOOK
day1probotlk_1200_torn
HAIL OUTLOOK
day1probotlk_1200_hail
WIND OUTLOOK
day1probotlk_1200_wind

Based on analysis of the SPC DAY 1 outlook, atmospheric conditions based on forecast soundings seem to indicate the probability of weak supercell development this afternoon over the SLIGHT risk area.  Based on the current outlook graphics and text, significant hail, wind, or tornadoes did not appear likely at the time of analysis.

Based on analysis of the current NAM – WRF model run, the following maps based on forecast indices indicate where the highest probability lies for the strongest of the severe weather categories.  Please note, the maps only go out to 7:00 p.m. CDT, as indices for the 10:00 p.m. time-frame were ambiguously scattered, and showed significant weakening.  This could change as the model updates later this morning, and/or should SPC make any changes to the risk outline or upgrade.

F5 DATA NAM-WRF 1:00 P.M. CDT
f5torn.1pm.
f5torn.1pm.2
F5 DATA NAM-WRF 4:00 P.M. CDT
f5torn.4pm.
F5 DATA NAM-WRF 7:00 P.M. CDT
f5torn.7pm.

SPC MESOSCALE DISCUSSIONS (CLICK IMAGE FOR UPDATES)

SPC CONVECTIVE WATCHES (CLICK IMAGE FOR UPDATES)


SPC HOME PAGE LINK
https://www.spc.noaa.gov/classic.html
The following NWS Watch / Warning map will provide local NWS information for your area.  Click the image, then once it refreshes, click on your area of interest to view any special weather statements, hazards or advisories for your area.
IF A TORNADO WARNING IS ISSUED FOR YOUR AREA, IMMEDIATELY TAKE STURDY AND SAFE SHELTER

NWS WATCH / WARNING DISPLAY (LINKED…CLICK MAP, THEN YOUR AREA)

WSI DOPPLER RADAR LOOP (LINKED)

RAP RADAR (CLICK IMAGE THEN RADAR SITE)

TROPICAL WEATHER OUTLOOK SYNOPSIS
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.  Beginning this season, the WMO has decided to no longer use the Greek alphabet, and came up with an alternate list of names, should we go past the names above.  The list of names are as follows:

Upon analysis of various tropical cyclone forecast parameters through various global models, the GFS model has been consistent now for the past 4 days of indicating a weak development in the GOMEX near the west coast of Florida, and taking it to the Louisiana coast.  The GFS has been infamous over the past seasons in developing systems in which no other global models indicate.  I know the model was recently upgraded, however it appears the problem of convective feedback still remains.  Analysis this morning of the global models shows the GFS still insisting on development, however has now switched to the east side of Florida.  The GFS indicates a closed low coming to fruition at around the day 9 -10 time frame.  Although the GFS has been consistent, I still do not see any  support from any other model as of this mornings analysis.  While the GFS does display SOME favorable parameters (warm SST’s, ample moisture from the surface to 700 mb), there are some unfavorable items in the mix such as wind shear, and no upper level outflow to speak of.  The ECMWF and CMC models do not indicate any favorable factors for development however.  Both models indicate the opposite forecast conditions of the GFS.  They indicate the presence of dry air, wind shear, and no 200 mb outflow.  The following model charts will pretty much show the story:
GFS MSLP ANOMALY FORECAST GIF
gfs-deterministic-gulf-mslp_norm_anom-1621058400-1621706400-1621922400-40
GFS 850 MB AND 700 MB RELATIVE HUMIDITY FORECAST
gfs-deterministic-gulf-rh850-1900800
gfs-deterministic-gulf-rh700-1900800
GFS 200 MB STREAMLINE MAP
gfs-deterministic-gulf-z200_speed-1900800
To save space and time, I am only posting the humidity forecast charts from the ECMWF and CMC models:
ECMWF
ecmwf-deterministic-gulf-rh850-1879200
ecmwf-deterministic-gulf-rh700-1879200
CMC
gem-all-gulf-rh700-1879200
Based on analysis of the current vertical wind shear and instability graphs, both the GOMEX and Atlantic ocean are under higher than average shear and lack of instability.  The graphs indicate these values based on climatology (climatology being the solid black line):
GOMEX WIND SHEAR
ts_al_gmx_VSHD
GOMEX INSTABILITY
ts_al_gmx_THDV
You can see from the graphs, that shear is above climatology, and instability is below climatology.  Same thing for the Atlantic Basin.

Based on analysis of the current MJO forecast (200 mb vertical velocity), conditions around the forecast time frame do not indicate favorable conditions for development.  The following maps indciate where either upward vertical motion (rising air), or downward vertical motion (sinking air) is forecast.  Blues and pinks = upward motion…Oranges and reds = downward motion.  Although development can sometime occur where sinking air is present, the sinking motion has to be weak, and development can be very slow.  The best conditions are where upward motion in the upper level of the atmosphere is occurring, as this creates divergence aloft, and convergence at the seas surface.  As air above is removed outward, Mother Nature takes care of this deficit by pooling in air at the surface, by convergence.  The air comes inward and collides, then rushes upward.  This begins the presence of a surface circulation.  The following are the current forecast maps for the MJO / 200 MB Vertical Velocities.
MJO
twc_globe_mjo_vp200
59
And finally, based on analysis of the ECMWF EPS Tropical Cyclone Formation Probability forecast, probabilities for development are very low at the moment for the forecast period.
ECMWF EPS CYCLONE PROBABILITIES 192 – 240 HOURS
eps_tropcyc_prob_20_carib_240
216 – 240 HOURS
eps_tropcyc_prob_20_carib_264
240 – 288 HOURS
eps_tropcyc_prob_20_carib_288
Current satellite imagery does not indicate any areas of interest at the moment, and water vapor imagery shows plenty of dry air across the Atlantic basin:
WEATHERNERDS GOES IR SATELLITE AND WATER VAPOR IMAGE LOOP
39358854
39358854.wv
Based on everything I analyzed this morning, and given the GFS is showing development 9 -10 days out in the forecast period and has shifted the location of development, I do not believe Tropical Cyclone development is expected during the next 7 days.  I will be monitoring the area however to see if ANY other models pick up on what the GFS sees, and if so, watch for consistency in the model runs.  As a rule with my hurricane forecasting, I prefer to not go out any further than 7 days in the forecast period, as the forecast becomes much less accurate that far out.  The preferred time frame is 5 days or less in my book.

You may direct any questions by contacting me personally, ANYTIME, at: twalsh22000@yahoo.com

Have a blessed day!

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

palmharborforecastcenter

2021-05-15 14:09:57

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