TROPICAL STORM DANNY FORECAST SYNOPSIS/TROPICAL SYNOPSIS…ISSUED AUG. 22, 2015…9:00 P.M. EDT

TROPICAL STORM FORMATION: DANNY, LOW (10%), MEDIUM (60%), MEDIUM (40%)

 

*SPECIAL NOTE: AT A LITTLE AFTER 9:00 P.M. THE ATCF AND NHC DESIGNATED THE WAVE WEST OF AFRICA INVEST 98L, LOCATED NEAR 13.3N;29.5W

ALL forecasts contained on this site,  are based on my analysis and knowledge of various forecast tools, including information contained in NHC products, and are not copies from any other entity.

*NOTE: In the TROPICAL STORM FORMATION line above, probabilities are for during the next 5 day period.  My personal probability will be listed as either NONE, MONITORING or PROBABLE.  This does not necessarily mean something will develop, but that certain forecast conditions are likely to be present, favoring development.  Once NHC products become available, then the appropriate probability and percentage will be used.

Please refer to the link for the Storm Prediction Center in the box at the top of the page, just below the Hurricane Hunter graphics.

For those who have donated to my site, your help has been greatly appreciated.  For those not aware, donations to my site help me offset my personal out of pocket expenses…such as some of the model maps you view on here, are only available due to my subscription to the corresponding site.  The F5 Data maps I post, also another out of pocket expense (monthly subscription).  Updates to software (weather related), and costs for my domain name are also out of pocket to me.  Any help you provide is immensely appreciated!  Although it may seem I am not here and working in support of your donation, I have to work my forecasting time around my ever changing work schedule.
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Current Storm Total for 2015:

TOTAL STORMS: 4
HURRICANES: 1
INTENSE HURRICANES: 1
U.S. LANDFALLS: 2

StormW Seasonal Forecast:

TOTAL STORMS:             8
HURRICANES:                   3
INTENSE HURRICANES: 1

Good evening everyone!

Danny has been downgraded to a Tropical Storm.  As of the 8:00 p.m. Intermediate Advisory, the following information was available on Danny:

Location: 15.6°N 54.1°W
Moving: W at 14 mph
Min pressure: 997 mb/29.44 in
Max sustained: 65 mph

NHC TRACKING MAP 5 DAY
235454W5_NL_sm

The initial motion provided from a Hurricane Hunter aircraft earlier was 285 degrees, or WNW, however the storms LLC has been moving west over the past couple of hours.  Based on current and forecast steering layers maps, I concur with the NHC, and I expect this motion to continue during the next 60-72 hours.  Thereafter, as I have been forecasting for the past 2 days, a strong weakness in the subtropical ridge develops in the mid and upper levels, and a little weaker in the low level steering.  Based on this, what may remain of Danny, should be drawn into a more NW motion, which is shown in the 5 day forecast track, and is also reflected in the dynamic track guidance models.

Based on my analysis of the forecast steering maps, this trof is a gradual development.  However, either the remnant or depression Danny, will be steered in the lower levels.  Given this, and with the look of the current forecast track from the NHC, whatever feature is left should mover over the northern Bahamas area, or slightly west of the northern Bahamas, in between the Florida peninsula, and the Bahamas, before being turned north then NE.  Again, this is based on the CURRENT run of the steering forecast, which is valid for 00Z this evening.  There is always the chance for subtle changes, if steering fluctuates between now and then.  However, at the moment, this seems to be the most plausible scenario at the moment.

ATCF DYNAMIC MODEL TRACK GUIDANCE 00Z
96L 00Z DYNAMIC GUIDANCE

Satellite loop images indicate that the LLC (Low Level Circulation) of Danny has become exposed to the SW of the mid and upper level circulation.  This is being caused by SWLY wind shear on the order of 20-25 knots over Danny.

DANNY FLOATER LOOP IMAGERY
avn0-laloDANNY

rgb0-danny

Water vapor loop imagery indicates a vast amount of dry air ahead of Danny, and outflow boundaries noted in RGB satellite loop imagery that Danny is beginning to ingest this dry air.  Based on the current wind shear forecast, upper level winds are forecast to remain unfavorable for any recovery.  Based on these factors, I concur with the NHC intensity forecast, which calls for Danny to continue gradual weakening.  By the end of the 5 day forecast period, Danny is forecast to be downgraded to a depression. 

DANNY FLOATER WATER VAPOR LOOP IMAGERY
wv0-lalodanny

CARIBBEAN SATELLITE LOOP IMAGERY
avnCAR-l

Currently, Tropical Storm Watches are in effect for portions of the northern islands.

From the NHC in Miami:

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:
A Tropical Storm Watch is in effect for…
* Antigua, Barbuda, Montserrat, St. Kitts, Nevis, and Anguilla
* Saba and St. Eustatius
* St. Maarten
* Guadeloupe, St. Barthelemy, and St. Martin

A Tropical Storm Watch means that tropical storm conditions are possible within the watch area, generally within 48 hours.

Interests elsewhere in the U. S. and British Virgin Islands, Puerto Rico, and the Dominican Republic should monitor the progress of Danny. Additional watches or warnings may be required for portions of these areas tonight or Sunday.

I will continue to monitor Danny during the next 72-96 hours for any significant changes to the steering pattern, and will try to have an update sometime tomorrow.  If not, my next update will be sometime on Tuesday.

Elsewhere, the NHC still indicates 3 areas of interest in the 5 day Graphical TWO.

NHC 5 DAY GTWO
two_atl_5d0

The area north of Bermuda was designated INVEST 97L yesterday evening.  The NHC has lowered the probability of development during the next 5 days to LOW (10%).  Upper level winds are not conducive for development at this time.  Although the NHC indicates there is some potential, this area is still associated with an upper level low, and is taking in dry air, which is plainly noted in water vapor imagery.  Based on this, I believe chances will be lowered again within the next couple of days.  This area should move to the north, then NE as it becomes merged with a front.

INVEST 97L WATER VAPOR LOOP IMAGERY
wv0-lalo97

A Tropical Wave located near 14.5N;28.0W has become slightly better organized today.  This wave is moving toward a westerly direction at around 25 mph.  Based on my analysis of the steering layers forecast, I expect this motion to continue during the next 72-96 hours, and coincides the the current NHC projected motion in the 5 day Tropical Weather Outlook.  Thereafter, the steering forecast will have to be reanalyzed to detect any changes that may occur.  As a general rule, I do not go out beyond 72-96 hours, as steering sometimes can change rapidly.

RAMSDIS CIRA METEOSAT 4 SATELLITE LOOP IMAGERY
tropical_met_4km_visir2_floater

tropical_met_4km_ir4_floater

The current wind shear map of the EATL indicates a small, elongated upper level anticyclone over the wave, and the shear forecast calls for this feature to move in tandem, not unlike what we just saw with the development of Danny.

Some dry air is note IVO of the wave, however conditions appear pretty similar to when we saw Danny develop.  IF convection can increase, the now warmer SST anomalies in the path may aid the wave in mixing out the dry air.

Based on these parameters and the fast forward speed of the wave, development should be slow to occur.  I will continue to monitor this feature during the next 72-96 hours for any significant changes.

Another wave is forecast to move off the African coast in the next few days.  The NHC has designated a MEDIUM (40%) probability for development during the next 5 days.  Upper level winds are forecast to become favorable for this area to slowly develop.  Development if any should be slow, due to drier air around this.  This feature should move toward the WNW initially, and based on my analysis of forecast steering, a sharp weakness develops in the subtropical ridge, and is forecast to steer this feature to the NNW in about 96 hours, then out to sea.  I will be monitoring this for any changes.

Have a blessed evening!

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

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About palmharborforecastcenter

I am a Tropical Forecast meteorologist, providing hurricane forecasts during the Atlantic Hurricane Season. I retired from the U.S. Coast Guard in July of 2001. Meteorology became my passion in high school, and I have continued my educational background in meteorology since 1996, when I undertook the study of Tropical Meteorology. While working toward my degree, I had to unexpectedly withdraw from college due to my oldest sons medical reasons. I do however, meet the educational criteria of the AMS to be recognized as a meteorologist. Studies include, but are not limited to the Navy Aerographers Mate course, Naval METOC meteorology course, Meteorology 2010 Sophomore level course while attending St. Petersburg College, Clearwater, FL., Basic Forecasting course for operational meteorologists from Rapid WX, meteorology institute, a four month meteorological internship, and extensive research on numerous meteorological topics such as the MJO, NAO, satellite imagery interpretation, etc. I have been forecasting Tropical Weather (Tropical Storms and Hurricanes) since 1996, with my main client being three different Coast Guard Commands.
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21 Responses to TROPICAL STORM DANNY FORECAST SYNOPSIS/TROPICAL SYNOPSIS…ISSUED AUG. 22, 2015…9:00 P.M. EDT

  1. David says:

    Hey, Storm Gang! Anybody up for setting-up a crowd-fund for StormW to buy a new PC with?

  2. dellamom says:

    Storm, just sent a little bit to help with the PC problem. I appreciate that it costs a whole lot for you to do what you do and I appreciate the benefit I get from your investment and your hard work. God bless you and yours.

  3. dellamom says:

    OK. I am a confused puppy here, Storm. Yesterday’s 5:00 pm AST report had Erika at 16.6 N 58.9 W. The 8:05 a.m. EDT discussion has her at 16.8N 61.5W. Today’s 11:00 a.m. AST report has her at 16.4 N 63.3 W. Apparently, she took a .4 degree southern jog? And the graphic has her taking a sudden NNW direction and then skirting the Florida coast. My simple brain in addled at this point. That’s why we need you, Storm. Thanks for being here for us.

  4. originallt says:

    Glad you are OK, Storm.

  5. Hi gang. My PC bit the dust, so I’m typing this from my from my fiancees Laptop. I have no access to my weather programs right now. However last look, Erika may skirt the FL. east coast, so the eastern seaboard is gonna have to keep an eye on her, as well as fl.

  6. David says:

    Hey, Storm!
    Hoping everything is okay over in Palm Harbor.
    We Pasco people are really missing your insights, and pray everything is okay with you and your family.
    Please update on Erika when you can..we need you!

    God bless

    D. in Land O Lakes

  7. Carol Nissen says:

    Stormy…. Where are you?

    Sent from my iPhone

    >

  8. Greg Goodman says:

    Mr storm I don’t like how this storm evolveing I think someone has upset mother nature.

    • dellamom says:

      I agree, Greg. It does not look good for Southern Florida right now, but things can always change.

      • Greg Goodman says:

        Dellamom weatherman said here no chance this is coming in gulf he said we are safe dellamom I hope Mr storm OK I am praying for him and his family.

        • dellamom says:

          I hope everyone is right and it doesn’t come here, Greg, but the way they are showing it skirting up the Florida coast, I have to pray hard for Florida. As all of us in coastal areas know, sitting offshore and skirting the coast is one of the worst ways to get a storm. You get all the force of a direct hit, but it doesn’t go away! It just continues to drag across you until it gets to the people next to you and, being over water, it doesn’t dissipate as quickly.

  9. dellamom says:

    Thank you, Storm, for all you do. Looks like the Cape Verde train is in motion, albeit a little late in the season. Prayers to those in the islands, because even a depression or a remnant low can be too much if it comes after several other small amounts of weather. I hope the next two “boxcars” of the train dissipate or go play with the fishes before getting there.

  10. originallt says:

    Thank you, Storm. Things are becoming pretty interesting. I guess the next 3-4 weeks is the “Heart’ Of the season, one might say.

  11. grannyMS says:

    Thank you Storm for keeping us informed with your excellent posts 🙂

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