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Hurricane Maria


Jtm12180

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2 minutes ago, NJwx85 said:

I was just trying to explain the difference between just a large hole in the center of a hurricane and a more traditional eye with an actual eyewall.

It's going to be a moot point soon anyway as convection is starting to wrap in close to the center again.

Its a closed wall on recon at 38 nm.  U really need to stop.  

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The probability of Maria's making landfall in the U.S. Mainland has declined overnight. The guidance came into somewhat better agreement concerning Jose's fate and, as a consequence, some of the uncertainty concerning Maria's fate was also reduced.

Based on hurricanes passing within 100 nautical miles of Maria's 8 am position (19.9°N 68.7°W), historical climatology (1851-present) showed approximately half making U.S. landfall. However, that figure significantly overstates the actual probability of Maria's making landfall.

When the pool is refined for those that made U.S. landfall and those that didn't, one comes up with the following numbers:

Average Longitude at 22.5°N Latitude:

U.S. Landfall: 74.6°W (σ=3.0°)
No. U.S. Landfall: 70.6°W (σ=2.3°)

Average Longitude at 25.0°N Latitude:

U.S. Landfall: 77.7°W (σ=3.3°)
No. U.S. Landfall: 71.9°W (σ=3.1°)

Maria is expected to be at more than 1 standard deviation to the east of average for storms that made U.S. landfall. It is also likely to be fairly close to the mean figure for those that did not make landfall. Overall, the adjusted data set implies a landfall figure of around 20%.

Fewer than 20% of the combined EPS and GEFS ensemble members show U.S. landfall. The 9/21 0z run of the ECMWF again indicates that Maria will not make landfall and it did not show the kind of closer call seen on the preceding 9/20 12z run.

Considering this data and the statistics for landfalling storms vs. those that did not make U.S. landfall from the climatological sample based on Maria's 8 am position, I believe the probability of U.S. landfall is now about 20%. U.S. landfall is very unlikely.

Finally, looking at past storms that were significantly weakened after crossing either Puerto Rico or Hispaniola (implying structural damage to their core), Maria probably won't see an increase in its maximum winds beyond 10 knots to 20 knots from its post-Puerto Rico figure (95 knots). The window of opportunity for intensification will likely begin to close within the next 18-36 hours, so unless a bout of rapid intensification occurs, it is unlikely that Maria will regain strength that exceeds maximum sustained winds of 105 knots (120 mph) to 115 knots (130 mph). However, intensity forecasting typically has low verification scores, so my confidence in these figures is no better than moderate.

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Also, I was clearly mistaken this morning with my assessment of the eyewall. I apologize for dragging the board down. Sometimes us amateurs need to eat a slice of humble pie and leave it up to the experts. If the staff feels that I should carry this ugly weenie tag then I guess so be it, but I like to think I make positive contributions.

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ZCZC MIATCDAT5 ALL
TTAA00 KNHC DDHHMM

Hurricane Maria Discussion Number  22
NWS National Hurricane Center Miami FL       AL152017
1100 AM AST Thu Sep 21 2017

Maria is maintaining a large, 40 nm wide eye, and overall, the
hurricane's satellite presentation has not changed since the
previous advisory.  An Air Force Reserve Hurricane Hunter aircraft
investigating the system has not measured flight-level winds as
high as last evening's mission, and the central pressure has
remained relatively steady.  Although there were higher SFMR winds
measured, especially to the northeast of the center, the flight
meteorologist reported that the instrument appears to be running
5-10 kt too high.  Therefore, the initial intensity is held at 100
kt.

Maria appears to be moving over the remnant cold wake leftover from
Hurricane Irma, but it should begin to move over an area of higher
oceanic heat content during the next 24 hours or so.  Therefore,
some strengthening is still forecast, although it is not especially
aggressive given what the latest intensity guidance is showing.
Gradual weakening is likely from 48 hours onward due to some
increase in southwesterly shear, as well as lower oceanic heat
content over the western Atlantic.  Still, Maria is expected to
remain a hurricane for the next 5 days.

The initial motion is northwestward, or 310/8 kt.  Maria will be
moving between a mid-level high centered south of Bermuda and a
broad trough extending from Tropical Storm Jose southwestward into
the northern Gulf of Mexico.  As a result, Maria is expected to
turn gradually north-northwestward to north-northeastward by the
end of the forecast period, keeping it over the waters of the
western Atlantic after moving by the Turks and Caicos Islands and
the southeastern Bahamas.  The track models continue to be tightly
clustered, and the updated NHC track forecast lies right along the
previous forecast, down the middle of the guidance envelope.
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Yesterday, the eyewall was in shambles after traversing Puerto Rico. That's the big difference today, it's a huge eye, but there's already an eyewall. Central pressure might be stable, but since we now have an eyewall, there's already a more significant gradient pressure in said eyewall and that's shown as the RMW now show cat 3 winds, whereas yesterday it didn't. Slow gradual strengthening for the next 48 hours is expected.

20170921_1221_gpm.x.89h_1deg.15LMARIA.100kts-959mb-199N-688W_42pc.thumb.jpg.6a1364c4802830da7353c877826603c5.jpg

 

With such a big eye, not only strengthening will be gradual, when the time comes, weakening will be at a slow rate, as big eyes are known to be relatively stable even on adverse conditions.

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000
URNT12 KNHC 211459
VORTEX DATA MESSAGE   AL152017
A. 21/14:40:50Z
B. 20 deg 08 min N
  069 deg 05 min W
C. 700 mb 2743 m
D. 93 kt
E. 306 deg 16 nm
F. 039 deg 103 kt
G. 308 deg 22 nm
H. 960 mb
I. 11 C / 3049 m
J. 15 C / 3047 m
K. 12 C / NA
L. CLOSED
M. C42
N. 1234 / 07
O. 0.02 / 1 nm
P. AF303 1215A MARIA              OB 17
MAX OUTBOUND AND MAX FL WIND 106 KT 132 / 20 NM 14:47:00Z
CNTR DROPSONDE SFC WIND 160 / 4 KT
MAX FL TEMP 18 C 306 / 13 NM FROM FL CNTR
;
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Just now, wxmx said:

Yesterday, the eyewall was in shambles after traversing Puerto Rico. That's the big difference today, it's a huge eye, but there's already an eyewall. Central pressure might be stable, but since we now have an eyewall, there's already a more significant gradient pressure in said eyewall and that's shown as the RMW now show cat 3 winds, whereas yesterday it didn't. Slow gradual strengthening for the next 48 hours is expected.

20170921_1221_gpm.x.89h_1deg.15LMARIA.100kts-959mb-199N-688W_42pc.thumb.jpg.6a1364c4802830da7353c877826603c5.jpg

 

With such a big eye, not only strengthening will be gradual, when the time comes, weakening will be at a slow rate, as big eyes are known to be relatively stable even on adverse conditions.

Yeah that's where I was mistaken. The ragged appearance of the eye on IR led me to believe that Maria was still trying to rebuild an inner core, however this microwave image as well as recon clearly indicates a large but stable eyewall.

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