SpoilerComo comenté hace unas horas atrás, el sistema que esta en el centro del atlántico tropical ya tiene esa "pinta" de que va a ser el primer gran huracán de tipo cabo verde de la temporada.
GFS atenta con una trayectoria similar a Irma pero un poco más al SW, respondiendo a una zona de alta presiones, idéntica a la que hizo virar a Irma. Veremos.
25KT - 1009MB
EPS 12z
Rosa/magenta/violeta (el color que sea): <950mb
ECMWF 12z da un categoría 4.
Son solo salidas pero da cuenta del ambiente favorable que tiene y que tendrá a priori.
Última edición por Wyoming el Mié Ago 26, 2020 2:45 pm, editado 5 veces en total.
NHC escribió:An area of low pressure located about 1300 miles east of the
Lesser Antilles is producing a concentrated area of showers and
thunderstorms. Environmental conditions are conducive for
development, and a tropical depression is expected to form within
the next couple of days while the system moves west-northwestward
at 15 to 20 mph across the central and western portions of the
tropical Atlantic. Interests in the Lesser Antilles should monitor
the progres of this system. * Formation chance through 48 hours...high...80 percent.
* Formation chance through 5 days...high...90 percent.
El sistema del este esta ligado a la ITCZ y pertenece a la misma circulación general que tiene esta enorme baja presión. No obstante, es un sistema aparte! Tal vez por la interacción de esta los modelos no explotan tanto a nuestro invest (98L, a la izquierda más al oeste). Tremendo si se le designa INVEST 99L Muchos modelos desarrolla este sistema pasando cerca de las islas principales o tocando tierra en ellas. Todo va a depender de que tan fuerte sea la zona de altas presiones en altura.
Va queriendo, no me sorprendería ver un PTC en breve. Spoiler
An elongated area of low pressure, located about 1000 miles east of
the Windward Islands continues to produce a concentrated area of
showers and thunderstorms. Although recent satellite-derived wind
data indicates that the low is not well-defined, environmental
conditions are conducive for further development, and a tropical
depression is expected to form during the next day or two while the
system moves generally west-northwestward at 15 to 20 mph across the
central and western portions of the tropical Atlantic. Interests
in the Lesser Antilles should monitor the progress of this system. * Formation chance through 48 hours...high...90 percent.
* Formation chance through 5 days...high...90 percent.
Sí, el PTC está al caer.
O tal vez lo clasifiquen directamente como depresión tropical en el aviso de las 23pm.
NHC escribió:Satellite images indicate that the low pressure system located about
850 miles east of the Windward Islands is gradually becoming better
defined. In addition, the associated showers and thunderstorms are
showing signs of organization, and a tropical depression could be
forming. The system is expected to move generally west-northwestward
at 15 to 20 mph, and interests in the northern Leeward Islands
should closely monitor its progress as tropical storm watches could
be required as early as this evening.
Tenemos al primero, 1/3. Mañana si la nombran toca Laura. Creo que rompería el récord de formación más temprana, actual Katrina 2005?
ASCAT-RAMMB muestra que no hay una circulación ciertamente cerrada en superficie. Sin embargo, un promedio ('blend') entre ASCAT y WINDSAT solucionan las ambigüedades que aparecen.
Acá se explica un mejor lo de estás 'ambigüedades' y sus soluciones, que recién estos días escuché sobre esto
Sinceramente no esperaba una depresión tan rápido.
GFS y Europa no veían nada hasta pasando las Antillas. Con esto probablemente empiecen a recalcular.
Wyoming escribió:Mañana si la nombran toca Laura. Creo que rompería el récord de formación más temprana, actual Katrina 2005?
El de Katrina ya lo rompió Kyle.
El de la tormenta con 'L' más temprana, curiosamente, no pertenece al 2005. Lo ostenta Luis que se formó el 28/8/95. Muy probablemente se rompa otro récord más.
Mensaje 2/2.
Ya salió la primer discusión del NHC. La dejo en spoiler; en negrita lo más importante. Spoiler
465
WTNT43 KNHC 200252
TCDAT3
Tropical Depression Thirteen Discussion Number 1
NWS National Hurricane Center Miami FL AL132020
1100 PM AST Wed Aug 19 2020
The low pressure system that NHC has been monitoring over the
central tropical Atlantic has now developed a well-defined center of
circulation and maintained enough organized deep convection to be
classified as a tropical depression, the thirteenth cyclone of the
2020 Atlantic hurricane season. The depression already has some
banding features on its north and west sides as evident in
geostationary satellite and microwave images. The initial intensity
is set at 30 kt based on ASCAT data from around 0100 UTC and a
T2.0/30 kt Dvorak classifications from TAFB.
The depression has been moving fairly quickly to the west-northwest,
with the latest initial motion estimated to be 295/17 kt. It should
be noted that the initial motion is somewhat uncertain given that
the system has only recently formed. A subtropical ridge currently
over the central Atlantic is expected to build westward during the
next several days and should be the primary steering feature for
the depression through the forecast period. This pattern should
keep the depression on a fairly quick west-northwest track during
the next several days, taking the cyclone near the northern
Leeward Islands by Friday night and near the Greater Antilles
and southeastern Bahamas this weekend. The models are in fairly
good agreement, but there is some north-south spread with the GFS
being on the southern side of the guidance envelope and the ECMWF
on the northern end. The NHC track forecast lies down the middle
of the guidance suite.
The environmental conditions appear generally favorable for the
depression to strengthen, with the wind shear expected to remain
relatively low while the system moves over warm SSTs and remains in
a moist airmass. These conditions should promote gradual
strengthening and it seems quite likely that the cyclone will be a
tropical storm when it moves near or north of the northern Leeward
Islands in a couple of days. The bigger question is how
much interaction will there be with the Greater Antilles. If the
depression moves on the south side of the guidance envelope,
further strengthening would be limited due to land interaction.
Conversely, if the system gains more latitude and moves north of
these highly topographic islands, it could have the opportunity for
more significant intensification. The NHC intensity forecast, which
is of low confidence, is roughly near the middle of the guidance
envelope.
Trayectoria oficial del NHC. Se pone muy interesante a priori..
maatii96 escribió: ↑Mié Ago 19, 2020 11:53 pm
El de la tormenta con 'L' más temprana, curiosamente, no pertenece al 2005. Lo ostenta Luis que se formó el 28/8/95. Muy probablemente se rompa otro récord más.
Bueno, la ascensión de depresión tropical a tormenta tropical hace que LAURA rompa el récord de la formación más temprana para una 12va tormenta (que hasta ayer lo mantenía Luis (cat5) en 1995) por 8 días.
000
WTNT63 KNHC 211305
TCUAT3
Tropical Storm Laura Tropical Cyclone Update
NWS National Hurricane Center Miami FL AL132020
905 AM AST Fri Aug 21 2020
...NOAA HURRICANE HUNTER AIRCRAFT FINDS THAT THE DEPRESSION HAS
STRENGTHENED TO TROPICAL STORM LAURA...
Data from a NOAA Hurricane Hunter aircraft indicate that Tropical
Depression Thirteen has strengthened and is now Tropical Storm
Laura with maximum sustained winds of around 45 mph (75 km/h). The
aircraft also found that the center of Laura is located south of the
previously estimated position. These changes will be reflected in
the track and intensity forecasts with the upcoming advisory that
will be issued at 1100 AM AST (1500 UTC).
SUMMARY OF 905 AM AST...1305 UTC...INFORMATION
---------------------------------------------------
LOCATION...17.0N 59.8W
ABOUT 230 MI...375 KM ESE OF THE NORTHERN LEEWARD ISLANDS MAXIMUM SUSTAINED WINDS...45 MPH...75 KM/H
PRESENT MOVEMENT...W OR 280 DEGREES AT 21 MPH...33 KM/H
MINIMUM CENTRAL PRESSURE...1008 MB...29.77 INCHES
$$
Forecaster Brennan/Pasch
Interesante lo que muestra el SHIPS: 24% de probabilidad de una RI de 65kt en las próximas 72hs.
Spoiler
* GFS version *
* ATLANTIC 2020 SHIPS INTENSITY FORECAST *
* IR SAT DATA AVAILABLE, OHC AVAILABLE *
* THIRTEEN AL132020 08/21/20 12 UTC *
FORECAST TRACK FROM OFCI INITIAL HEADING/SPEED (DEG/KT):275/ 18 CX,CY: -17/ 2
T-12 MAX WIND: 30 PRESSURE OF STEERING LEVEL (MB): 643 (MEAN=620)
GOES IR BRIGHTNESS TEMP. STD DEV. 50-200 KM RAD: 15.8 (MEAN=14.5)
% GOES IR PIXELS WITH T < -20 C 50-200 KM RAD: 82.0 (MEAN=65.0)
PRELIM RI PROB (DV .GE. 35 KT IN 36 HR): 22.2
** 2020 ATLANTIC RI INDEX AL132020 THIRTEEN 08/21/20 12 UTC **
(SHIPS-RII PREDICTOR TABLE for 30 KT OR MOREMAXIMUM WIND INCREASE IN NEXT 24-h)
Predictor Value RI Predictor Range Scaled Value(0-1) % Contribution
12 HR PERSISTENCE (KT) : 10.0 -49.5 to 33.0 0.72 5.9
850-200 MB SHEAR (KT) : 14.5 30.1 to 2.3 0.56 1.8
HEAT CONTENT (KJ/CM2) : 52.8 0.0 to 151.8 0.35 1.0
STD DEV OF IR BR TEMP : 15.8 36.6 to 2.8 0.62 2.1
MAXIMUM WIND (KT) : 40.0 22.5 to 137.5 0.46 0.8
2nd PC OF IR BR TEMP : 1.8 2.9 to -2.9 0.20 0.4
BL DRY-AIR FLUX (W/M2) : 210.6 895.4 to -55.0 0.72 1.5
POT = MPI-VMAX (KT) : 113.6 27.5 to 139.6 0.77 0.6
D200 (10**7s-1) : 8.2 -29.7 to 185.9 0.18 0.1
%area of TPW <45 mm upshear : 0.0 100.0 to 0.0 1.00 0.2
SHIPS Prob RI for 20kt/ 12hr RI threshold= 8% is 1.5 times climatological mean ( 5.0%)
SHIPS Prob RI for 25kt/ 24hr RI threshold= 21% is 1.9 times climatological mean (10.9%)
SHIPS Prob RI for 30kt/ 24hr RI threshold= 15% is 2.1 times climatological mean ( 6.9%)
SHIPS Prob RI for 35kt/ 24hr RI threshold= 12% is 3.1 times climatological mean ( 3.9%)
SHIPS Prob RI for 40kt/ 24hr RI threshold= 10% is 4.1 times climatological mean ( 2.5%)
SHIPS Prob RI for 45kt/ 36hr RI threshold= 13% is 2.8 times climatological mean ( 4.6%)
SHIPS Prob RI for 55kt/ 48hr RI threshold= 14% is 3.0 times climatological mean ( 4.6%) SHIPS Prob RI for 65kt/ 72hr RI threshold= 24% is 4.6 times climatological mean ( 5.2%)
## ANNULAR HURRICANE INDEX (AHI) AL132020 THIRTEEN 08/21/20 12 UTC ##
## STORM NOT ANNULAR, SCREENING STEP FAILED, NPASS=4 NFAIL=3 ##
## AHI= 0 (AHI OF 100 IS BEST FIT TO ANN. STRUC., 1 IS MARGINAL, 0 IS NOT ANNULAR) ##
** PROBLTY OF AT LEAST 1 SCNDRY EYEWL FORMTN EVENT AL132020 THIRTEEN 08/21/2020 12 UTC **
TIME(HR) 0-12 12-24(0-24) 24-36(0-36) 36-48(0-48)
CLIMO(%) 0 0( 0) 0( 0) 0( 0) <-- PROB BASED ON INTENSITY ONLY
PROB(%) 0 0( 0) 0( 0) 0( 0) <-- FULL MODEL PROB (RAN NORMALLY)
Muchos modelos desarrolla este sistema pasando cerca de las islas principales o tocando tierra en ellas. Todo va a depender de que tan fuerte sea la zona de altas presiones en altura. 
