TROPICAL DISTURBANCE INVEST 98L FORECAST SYNOPSIS…PROBABLE INCREASE IN EATL ACTIVITY DISCUSSION…ISSUED AUG. 15, 2016…11:25 A.M. EDT

TROPICAL CYCLONE FORMATION: INVEST 98L (30%)

Disclaimer:  This site is not affiliated with the National Hurricane Center, Storm Prediction Center, or National Weather Service.  ALL forecasts herein are the result of my analysis, and I am solely responsible for the content.
(T. F. “Storm” Walsh III)

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CURRENT 2016 ATLANTIC TROPICAL CYCLONE TOTALS:

TOTAL STORMS: 5
HURRICANES: 2
INTENSE HURRICANES: 0
U.S.LANDFALLS: 2

StormW’s Seasonal Hurricane Forecast:
TOTAL STORMS: 13-15
HURRICANES: 6-7
INTENSE HURRICANES: 3-4

Good day everyone!

The area of disturbed weather I mentioned in yesterdays forecast, was designated INVEST 98L yesterday evening by the NHC.  The NHC has designated a LOW (30%) probability of tropical cyclone formation during the next 5 days.

NHC 5 DAY GRAPHICAL TROPICAL WEATHER OUTLOOK
two_atl_5d0

Various modeling indicates some higher probability of development.

ECMWF TCPROB
eps_tcprob_20_atlantic_1

eps_tcprob_20_atlantic_2

NOAA TCFP
al_rTCFP_048

NCEP EMC
genprob.4enscon.2016081506.altg.000_048

Based on information contained in the ATCF BTK product as of 12Z, the following was available on INVEST 98L:

8:00 AM EDT Mon Aug151
Location: 9.2°N 23.7°W
Moving: W at 15 – 18 mph
Min pressure: 1009 mb/29.80 in
Max sustained: 25 mph

The disturbance is currently moving toward the west, with a 24 hour average speed of 15-18 mph.  INVEST 98L is currently being steered by the southern periphery of the sub-tropical ridge.  At the moment, I am in some disagreement with the future projected track in the NHC GTWO, and with the current 12Z dynamic track guidance.  I am having a tendency to somewhat agree with the current ECMWF forecast track, however based on my analysis of the current steering layer mean, and forecast steering maps from the PSU E-wall site, I believe a more westward track will be in order, as current steering, and satellite loop imagery indicates a pretty straight east to west flow at the moment.  IF the current run of the forecast steering maps is accurate, I expect a west, to slightly north of west track to continue for at least the next 36 hours, possibly 48 hours, before a weakness in the ridge occurs at around 45W.  Based on satellite loop imagery, noting low and mid level cloud motion, combined with the forecast steering layers maps, I am just not buying the quick turn toward the WNW-NW as depicted in dynamic guidance.  IF dynamic guidance beats me, then as in the past, I’ll have to re-analyze what has been looked at in analysis.

INVEST 98L FLOATER SATELLITE LOOP IMAGERY
avn0-lalo98L

RAMSDIS METEOSAT LOOP
tropical_met_4km_ir4_floater

CATL SATELLITE LOOP
avn-lcatl

CURRENT STEERING LAYER
wg8dlm1

ATCF 12Z DYNAMIC MODEL GUIDANCE
98L 12Z DYNAMIC GUIDANCE

INVEST 98L hasn’t change much in organization in the past few hours, and appears elongated at the moment.  Based on the recent wind shear product from CIMSS, a weak upper level anticyclone was established over the disturbance, and the disturbance was located in a high TPW environment.

INVEST 98L WIND SHEAR AND TPW ENVIRONMENT
tccaptureshear98l

tccapturetpw98L

MIMIC TPW
latest72hrs

Water vapor loop imagery indicates there may be enough moisture for INVEST 98L to fight off any African dust.

METEOSAT WATER VAPOR LOOP
wv-leatl

Based on my analysis of the GFS wind shear product, the upper level anticyclone is forecast to diminish somewhat, but could become re-established over the system in 2-3 days.  Analysis of forecast shear magnitude from the NOAA RUC HFIP TCDIAG. page, indicates the ECMWF and GFS both call for shear to decrease to below 10 kts within the next 36 hours.

Should this come to fruition, save any significant dry air intrusion, I am calling for further slow strengthening of INVEST 98L.  Current ATCF Intensity guidance indicates the more reliable intensity models bring 98L to strong Tropical Storm to Minimal CAT1 Hurricane status in 4-5 days.  Given that both track guidance and intensity guidance have just been initialized, I am just going to keep this in the back of my mind, until modeling can complete a couple of more runs, or until 98L possibly becomes better organized…however if the shear forecast is correct, I CANNOT rule out the intensity guidance at the moment.

ATCF 12Z INTENSITY GUIDANCE
98L 12Z INTENSITY GUIDANCE

I will continue to monitor INVEST 98L for any significant changes during the next 2 days.

Elsewhere, if the global models are correct…STANDBY.  As of this mornings run of the GFS and ECMWF, believe it or not, both models are in uncanny agreement of activity increasing over the next 7-10 days, indicating a total of 3 active systems before the end of the month.  Based on my analysis of the models this morning, both the ECMWF and GFS eventually re-curve 98L, and another system that is forecast to exit Africa a little further north than an area forecast to exit Africa at the same time frame, in about 5-6 days.  This can be seen in both the GFS and ECMWF.  The system that exits further south, is projected by the models to come to around 50W, before making a turn to the WNW.  Based on analysis of the medium to long range 500 mb pattern, this feature should feel a weakness off the U.S. east coast, which will bring it to the WNW.  However, indications are this weakness may be the precursor to a trof split, where the main piece will shoot NNE, and another backs away toward the GOMEX.  IF this occurs, the possibility of ridging building back over the feature, COULD bring it close to FL. or the U.S. coastline.  This is not written in stone, but is one possible scenario, should the activity occur.  Right now, I cannot rule this uptick out, as the recent forecast of the 200 mb velocity potential anomalies indicates favorable conditions during the next 5-7 days.  The current NASA TPW forecast still indicates moist surges to continue to exit Africa.

GFS MSLP ANOMALY FORECAST
gfs_mslp_sig_catl_39
ECMWF MSLPA FORECAST
ecm_mslpa_catl_11
Analysis of the 500 mb anomaly maps tends to indicate we may see the African wave train come more to life in about 7-10 days, as lowering pressures are noted over the African continent.

GFS AND ECMWF 500 MB ANOMALY FORECAST
gfs_z500_sig_catl_40

ecm_z500_anom_catl_11

NASA TPW FORECAST
nasa_pwat_atlantic_21

nasa_pwat_atlantic_25

nasa_pwat_atlantic_39

Elsewhere, Tropical Storm formation is not expected during the next 5-7 days

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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6 Responses to TROPICAL DISTURBANCE INVEST 98L FORECAST SYNOPSIS…PROBABLE INCREASE IN EATL ACTIVITY DISCUSSION…ISSUED AUG. 15, 2016…11:25 A.M. EDT

  1. Greg Goodman says:

    Thankyou Mr storm

  2. dellamom says:

    We have been experiencing severe flooding throughout southern Louisiana, predominantly from the Lake Pontchartrain Causeway westward. More damage than we sometimes see in a hurricane. Thank you for all of your excellent work and teachings.

  3. Ethan says:

    Where are the last picture from what website

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