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Great pics, you guys!! I'm visiting family stateside, trying to keep an eye on Zeta. Since I'm traveling, I'm using dialup... 15 minutes to load this page - arghhh! The sat pics are murder at this speed, but who can live without them? I can't!!
Zeta continues to generate convective tops of -55c to -60c near the
low-level center....with ragged outer banding over the northeastern
semicircle. Some anticyclonic outflow was apparent in cirrus cloud
motions earlier. However...this has decreased over the past few
hr. Satellite intensity estimates continue to range from 65 kt at
TAFB to 45 kt at AFWA and are essentially unchanged from 6 hr ago.
Thus...the initial intensity remains 55 kt.
Zeta has moved more toward the south and faster over the past 6-12
hr...likely due to interaction with an upper-level low seen in
water vapor imagery near 21n38w. However...the last few images
suggest a more westward motion...and the initial motion is thus a
somewhat uncertain 220/6. Zeta is south of a mean deep-layer ridge
over the central Atlantic...while a mean deep-layer trough is over
the western Atlantic. A shortwave trough and surface front are
currently between the eastern United States and Bermuda...while
large-scale models suggest a second stronger shortwave will move
into the western Atlantic after 48 hr. The new trough will cause
the first shortwave trough to move northeastward north of Zeta...
with the ridge re-building in between the troughs. This evolution
should cause the storm to turn northwestward during the next 48-72
hr...then turn more westward thereafter as the ridge re-builds.
The dynamical models generally agree on this...with the exception
of the UKMET which calls for recurvature along 48w in 48-72 hr.
The official forecast will follow the scenario suggested by the
other dynamical models...and is similar to but west of the previous
forecast. The new forecast is in best agreement with the GFDL.
Zeta is well embedded in upper-level westerlies between the
subtropical and polar jet streams...which overall is not a very
favorable environment. The large-scale models suggest a series of
upper-level short-wave features will pass over Zeta during the next
48 hr...most notably the southern end of the current western
Atlantic trough which should reach the storm in about 36 hr. This
pattern should produce some surges and lulls in vertical shear...
and based on this the intensity forcast calls for slow weakening
for 48 hr. After that...a building upper-level ridge west of Zeta
should cause 40-50 kt upper-level northwesterly flow over the
storm...which should cause significant weakening. Therefore...the
intensity forecast shows Zeta weakening to a depression by 72 hr
and dissipating by 120 hr. It should be noted that the GFDL still
wants to make Zeta a hurricane...and there is a small chance the
the approaching shortwave trough could briefly provide a more
favorable environment for strengthening in about 36 hr.
04/1145 UTC 21.9N 43.6W T2.5/3.5 ZETA -- Atlantic Ocean
SSD dvorak T numbers are starting to decrease as the system looks ragged as it's demise is slowly arriving.
TPNT KGWC 041208 A. TROPICAL STORM ZETA (THIRTY) B. 04/1131Z (139) C. 22.0N/4 D. 43.4W/1 E. FOUR/GOES12 F. T2.0/3.0/W0.5/24HRS -04/1131Z- G. IR/EIR
38A/ PBO SBC/ ANMTN. CNVCTN WRAPS .40 ON LOG10 SPIRAL YIELDING A DT OF 3.0. FT BASED ON DT. PT AND MET AGREES.
AODT: T4.3 (SHEAR)
HEATH
Air Force sat estimates are down too.
Now let's see if the 12:00z models show a decrease in intensity.
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Still the circulation looks very tight and impressive with those curved bands of low clouds although the convection has been on the decline.Movement is still westward maybe a tad westsouthwestward.
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WHXX04 KWBC 041720 CHGQLM ATTENTION...NATIONAL HURRICANE CENTER
NCEP COUPLED GFDL HURRICANE MODEL FORECAST MADE FOR
TROPICAL STORM ZETA 30L
INITIAL TIME 12Z JAN 4
DISCLAIMER ... THIS INFORMATION IS PROVIDED AS GUIDANCE. IT REQUIRES INTERPRETATION BY HURRICANE SPECIALISTS AND SHOULD NOT BE CONSIDERED AS A FINAL PRODUCT. PLEASE SEE THE TPC/NHC OFFICIAL FORECAST.
Finnally GFDL at it's 12z run drops Zeta at 96 hours.
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18:00z Models decrease more the intensity now down to 45kts.
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slartibartfast wrote:Do we continue to count the ACE numbers in the 2005 column despite the storm surviving into 2006? Mark
According to what I read in this same forum, 1954 received the ACE numbers of Alice life in 1955 since the storm formed in 1954. So, I think since Zeta formed in 2005, its ACE numbers of 2006 will go toward 2005!