Hardcore Weather

Full Version: HURRICANE IRMA
You're currently viewing a stripped down version of our content. View the full version with proper formatting.
Thank you for all the information, so many people will be affected by Irma, I guess the big question for me... "Is the storm shifting?, could it possibly move out to the Atlantic with no direct hit to the US?"
Checkout Brett Adair on Live Storm Chasing! https://livestormchasing.com/stream/brett.adair
Quote:https://t.co/7bJZcxCTNx #HurricaneIrma #FEMA #Florida WHY?? Miami is only 7 ft above sea level. Houston is 80 ft above sea level. #Irma2017
— David Perrodin, PhD (@SafetyPhD) 6 Sep 2017
RECON COC DATA:

[Image: recon_AF305-1311A-IRMA_dropsonde3_20170906-1626.png]


[Image: recon_AF305-1311A-IRMA_timeseries.png]


EYE WALL DROPSONDE:


Product: Air Force Temp Drop (Dropsonde) Message (UZNT13 KNHC)
Transmitted: 6th day of the month at 16:43Z
Agency: United States Air Force
Aircraft: Lockheed WC-130J Hercules with reg. number AF97-5305
Storm Number: 11
Storm Name: Irma (flight in the North Atlantic basin)
Mission Number: 13
Observation Number: 09

Part A...

Date: Near the closest hour of 16Z on the 6th day of the month
Highest Mandatory Level For Which Wind Was Reported: 850mb
Coordinates: 18.5N 64.5W
Location: 9 statute miles (15 km) to the ENE (58°) from Road Town, British Virgin Islands (U.K.).
Marsden Square: 043

Surface and Standard Isobaric Surfaces
Level Geo. Height Air Temp. Dew Point Wind Direction Wind Speed
Unavailable Surface (Sea Level) Information Unavailable
1000mb Information Unavailable
925mb 119m (390 ft) 23.8°C (74.8°F) 22.9°C (73°F) 315° (from the NW) 152 knots (175 mph)
850mb 859m (2,818 ft) 20.8°C (69.4°F) 20.2°C (68°F) 345° (from the NNW) 172 knots (198 mph)
700mb 1,531m (5,023 ft) Height extrapolated since sonde was released within 25mbs below this level.

Information About Radiosonde:
- Launch Time: 16:23Z
- About Sonde: A descending radiosonde tracked automatically by satellite navigation with no solar or infrared correction.

Remarks Section...

Dropsonde Location: Dropped in eyewall 315° (NW) from the eye center.

Highest altitude where wind was reported:
- Location: 18.46N 64.52W
- Time: 16:23:44Z

Lowest altitude where wind was reported:
- Location: 18.27N 64.53W
- Time: 16:29:14Z

Average Wind Over Lowest Available 150 geopotential meters (gpm) of the sounding:
- Lowest 150m: 113 gpm - -37 gpm (371 geo. feet - -121 geo. feet)
- Wind Direction: 305° (from the NW)
- Wind Speed: 135 knots (155 mph)

Sounding Software Version: AEV 33304

Undecoded Remarks (Our system could not determine how to decode this text)...

LST WND -37

Part B: Data for Significant Levels...

Significant Temperature And Relative Humidity Levels
Level Air Temperature Dew Point
941mb 25.2°C (77.4°F) 24.7°C (76°F)
850mb 20.8°C (69.4°F) 20.2°C (68°F)
715mb 16.4°C (61.5°F) 15.6°C (60°F)
700mb 14.2°C (57.6°F) 14.2°C (58°F)

Significant Wind Levels
Level Wind Direction Wind Speed
941mb 305° (from the NW) 110 knots (127 mph)
940mb 305° (from the NW) 124 knots (143 mph)
939mb 305° (from the NW) 125 knots (144 mph)
936mb 305° (from the NW) 127 knots (146 mph)
935mb 305° (from the NW) 119 knots (137 mph)
930mb 305° (from the NW) 146 knots (168 mph)
927mb 310° (from the NW) 155 knots (178 mph)
920mb 315° (from the NW) 142 knots (163 mph)
918mb 310° (from the NW) 146 knots (168 mph)
915mb 320° (from the NW) 162 knots (186 mph)
914mb 325° (from the NW) 164 knots (189 mph)
906mb 330° (from the NNW) 140 knots (161 mph)
900mb 335° (from the NNW) 140 knots (161 mph)
893mb 335° (from the NNW) 148 knots (170 mph)
878mb 340° (from the NNW) 181 knots (208 mph)
867mb 340° (from the NNW) 191 knots (220 mph)
860mb 345° (from the NNW) 181 knots (208 mph)
850mb 345° (from the NNW) 172 knots (198 mph)
839mb 355° (from the N) 175 knots (201 mph)
833mb 0° (from the N) 152 knots (175 mph)
826mb 0° (from the N) 165 knots (190 mph)
819mb 5° (from the N) 150 knots (173 mph)
793mb 5° (from the N) 150 knots (173 mph)
782mb 15° (from the NNE) 130 knots (150 mph)
767mb 20° (from the NNE) 129 knots (148 mph)
759mb 20° (from the NNE) 149 knots (171 mph)
756mb 25° (from the NNE) 130 knots (150 mph)
749mb 30° (from the NNE) 137 knots (158 mph)
747mb 30° (from the NNE) 136 knots (157 mph)
726mb 20° (from the NNE) 90 knots (104 mph)
711mb 30° (from the NNE) 120 knots (138 mph)
709mb 35° (from the NE) 107 knots (123 mph)
700mb 25° (from the NNE) 108 knots (124 mph)

Winds at a particular level are peak winds since a dropsonde only records momentary slices of data at each level as it falls through the atmosphere. These winds are not 1 minute sustained.

The highest wind observed in the "Significant Wind Levels" section is noted in bold.
Jeff Masters

Quote:

Weather Underground Category 6

Breaking news about weather, climate & air quality



[Image: irma-viirs-sep6.jpg]

Category 5 Irma Hits Leeward Islands at Peak Strength




Bob Henson

·

September 6, 2017, 12:40 PM EDT





Above: VIIRS
infrared image of Hurricane Irma taken at 1:35 am EDT Wednesday,
September 6, 2017. At the time, the island of Barbuda was in the eye,
and Irma was a Category 5 storm with 185 mph winds. Image credit: UW-Madison/CIMSS.
Hurricane Irma smashed into the small Lesser Antilles islands of Barbuda (population 1,638), Saint Barthelemy (population 9,000), Anguilla (population 15,000), and Saint Martin/Sint Maarten
(population 8,000/33,000) early Wednesday as a mighty Category 5
hurricane with 185 mph winds. As the front southwestern eyewall of Irma
hit, Barbuda reported
sustained winds of 118 mph, gusting to 155 mph, before the instrument
failed. The minimum pressure in the eye was 916 mb on Barbuda and St.
Barthelemy. Preliminary reports from these islands indicate heavy wind
and storm surge damage occurred. On Saint Martin, storm surge flooding
to rooftop level was observed. Irma brought a storm surge of 7.95 feet (2.42 meters) to Barbuda, according to a Wednesday afternoon blog post by storm surge scientist Dr. Hal Needham. Barbuda has not been heard from yet.
A
hurricane with top winds of 185 mph has never been recorded in these
islands, and Irma’s landfall intensity of 185 mph winds in the Leeward
islands is tied with the 1935 Florida Keys Labor Day Hurricane as the
highest landfall intensity on record for an Atlantic hurricane (third
place globally.) The most recent close analog for Irma may be Hurricane Hugo (1989), which tore through the Leewards and struck Puerto Rico as a Category 4 storm, causing $3 billion in damage (1989 dollars) and 72 deaths.
Quote:Wat eerste foto's vanuit het Franse deel van St Maarten. Deel twee van #Irma is nu gaande (via Kevin Carty) pic.twitter.com/hVaAzxliLS
— Michel Spekkers (@spekkers) September 6, 2017
[Image: barbuda-radar.png]Figure 1. Radar image of Irma taken at 1 am EDT September 6, 2017. The island of Barbuda is in the southwestern portion of the eye. A long loop of the radar (courtesy Brian McNoldy) shows the track of Irma over Barbuda and the Leeward Islands. Image credit: Meteo France.
[Image: irma-moonlight-sep6.jpg]Figure 2.
Hurricane Irma as seen in moonlight by the VIIRS instrument on the
Suomi satellite at approximately 3 am EDT Wednesday, September 6, 2017.
Barbuda was in the southeastern eyewall of Irma at this time. Puerto
Rico is visible at the left of the image. Image credit: NASA.
[Image: strongest-landfaling-tcs.png]Figure 3.
Irma’s landfall intensity of 185 mph winds in the Leeward islands is
tied with the 1935 Florida Keys Labor Day Hurricane as the highest
landfall intensity on record for an Atlantic hurricane, and is in third
place globally.
Next targets: British Virgin Islands, U.S. Virgin Islands, and Puerto Rico
On
Wednesday afternoon, Irma will make a direct hit on the British Virgin
Islands, including Virgin Gorda (population 4,000), and Tortola
(population 9,000.) The southern eyewall of Irma is also likely to
affect the island of Saint John (population 4,000) in the U.S. Virgin Islands. A personal weather station on the south shore of St. Thomas measured sustained winds of 94 mph at 12:33 pm Wednesday. The island of Saint Thomas
(population 52,000) may barely miss the eyewall of Irma, but
northeastern portions of the island are still likely to receive
sustained Category 1 hurricane winds of 75 – 90 mph. The same holds true
for Puerto Rico’s Culebra Island. The extreme northeast corner of
Puerto Rico should see slightly lower winds, near 60 – 80 mph.
[Image: irma-radar-sep6.png]Figure 4.
Radar image of Irma from the Puerto Rico radar at 11:35 am EDT
September 6, 2017. The northwest eyewall was over the British Virgin
Islands.
Longer-range outlook for Irma: Cuba, the Bahamas, and Southeast U.S.
Computer
model guidance has begun to consolidate somewhat on Irma’s future
during the period from Saturday onward, but there remains major
uncertainty on exactly where Irma will track. Our top three track
models—the European, GFS, and UKMET models—continue to agree strongly
that Irma will continue on a west-northwest track through at least
Friday. NHC predicts that Irma will still be a Category 5 hurricane
through at least Friday morning. By late Thursday, Irma will likely be
in or near the Southeast Bahamas, which are under a Hurricane Warning,
with a Hurricane Watch for the Central Bahamas as of Wednesday morning.
Some of the islands of the Southeast Bahamas may take a direct hit from
Irma, and other islands may wind up in the dangerous right-hand side of
the storm. Irma has the potential to be a devastating storm for
The Bahamas, especially its southern islands, and residents should rush
any needed preparations to completion.

By Saturday, there
is fairly strong model agreement that Irma will be located somewhere
between the western Bahamas and Cuba, still on its west-northwest track.
Irma will be paralleling the north coast of Cuba, and it is possible
Irma’s center will move just inland along the coast for some period of
time; parts of the north coast of Cuba are within the “cone of
uncertainty” in the official NHC forecast. Residents of Cuba will need to pay very close attention to Irma’s track.
The eastern two-thirds of Cuba was under a Hurricane Watch as of
Wednesday morning. Irma is not expected to cross Cuba and move into the
Caribbean.
[Image: 145453_most_likely_toa_34.png]Figure 5. Most likely arrival time of tropical-storm-force winds from Irma, as of the 11 am EDT Wednesday, September 6, 2017 advisory from NHC.
Models
have been very consistent that Irma will take a sharp turn toward the
north-northwest during the weekend, working its way around the west end
of an upper-level ridge that has been steering Irma all week. The
crucial question is exactly where and when Irma will take this
right-hand turn, as that will play a huge role in possible impacts to
the Southeast U.S. coast. Our top models shifted eastward on Tuesday
night in their predictions of where the right-hand turn will occur, and
the consensus is now that Irma is most likely to track from south to
north either across the Florida Peninsula or just east of it, perhaps
remaining near the coastline until moving further inland somewhere from
Georgia to North Carolina. Irma is not expected to track sharply away
from the Southeast U.S. coastline. A track along or just off the west
coast of Florida is still possible. None of our reliable models bring
Irma any further west than the Florida Panhandle, so the chance of Irma
moving deeply into the central or western Gulf is increasingly remote. A
track that curves north and stays just east of Florida is also
possible; such a track could still bring Irma into the East Coast at a
point further north early next week. Figures 6, 7 and 8 below show the
range of possibilities in ensemble model guidance from Tuesday night
(ensemble models include a number of parallel forecasts that reflect the
uncertainty in a given weather situation).
In short,
computer guidance is in strong agreement that Irma will make at least
one landfall somewhere from Florida to North Carolina during the weekend
or early next week. The official NHC forecast track as of 11 am Wednesday brings Irma from near Miami to near Daytona Beach from Sunday morning to Monday morning. The 12Z Tuesday run of the GFS model predicts that Irma will hit Miami on Sunday afternoon, then make a second landfall near the Georgia/South Carolina border on Monday afternoon, with both landfalls occurring with at least Category 4 strength.
The
entire Florida peninsula and southeast Georgia are within the five-day
cone of uncertainty in the official NHC forecast, and all residents of
these areas should pay especially close attention to the progress of
Irma. Residents of southeast Florida need to be especially vigilant.

Intensity and storm surge
By
the time of its turn, Irma is still predicted to be a Category 4
hurricane by NHC, and the GFS and European forecast models imply that
Irma could be close to Category 5 strength, especially if its center
does not move onshore across northern Cuba. Wind shear is predicted to
remain low to moderate along Irma’s path until Saturday, and Irma will
be passing over waters that are as warm or slightly warmer than its
current environment, so there is nothing that would be expected to cause
major weakening of Irma other than potential land interactions,
especially with Cuba. As Irma moves northward, increasing wind shear and
interactions with land will likely begin to weaken Irma. However, Irma
is expected to remain a major hurricane well after its northward turn,
even if its center moves over the Florida peninsula and especially if
the center remains just off the coast. The official NHC forecast

as of 11 am Wednesday has Irma as a Category 3 storm on the east-central Florida coast on Monday morning.
Because
of Irma’s long life and its extreme strength, Irma will be pushing a
tremendous amount of water through the Bahamas in the form of high waves
and storm surge. Even if Irma’s winds weaken and its
Saffir-Simpson category drops, Irma could still be capable of extreme
storm surge, depending on its track and the geography of its landfall
location(s).
Storm surge expert Dr. Hal Needham noted in a blog post
Wednesday: "The region from northeast Florida (St. Augustine) through
all of the Georgia coast and southwest South Carolina is particularly
vulnerable to storm surge, whether or not Irma makes a direct landfall
in that region."
[Image: cfan-gfs-0Z-9.6.17.jpeg]Figure 6. The 20 track forecasts for Irma from the 0Z Wednesday, September 6, 2017 GFS model ensemble forecast. Image credit: CFAN.
[Image: cfan-eur-0Z-9.6.17.jpeg]Figure 7. The
0Z September 6, 2017, track forecast by the operational European model
for Irma (red line, adjusted by CFAN using a proprietary technique that
accounts for storm movement since 0Z Wednesday), along with the track of
the average of the 50 members of the European model ensemble (heavy
black line), and the 50 track forecasts from the 0Z Wednesday European
model ensemble forecast (grey lines). Image credit: CFAN.
[Image: cfan-eur-hi-res-0Z-9.6.17.jpeg]Figure 8.
The 0Z September 6, 2017, track forecast by the operational European
model for Irma (red line, adjusted by CFAN using a proprietary technique
that accounts for storm movement since 0Z Wednesday), along with the
track of the average of the 50 members of the European model ensemble
(heavy black line), and the track forecasts from the “high probability
cluster” (grey lines)—the four European model ensemble members that have
performed best with Irma thus far. All of these variations bring Irma
very close to the Miami-Fort Lauderdale-Palm Beach corridor. Image
credit: CFAN.
[Image: katia-irma-jose-1530Z-9.6.17-annotated.jpg]Figure 9.
Infrared satellite image of Katia, Irma, and Jose as of 1530 (11:30 am
EDT) Wednesday, September 6, 2017. Image credit: NASA/MSFC Earth Science
Branch.
Meanwhile, we have Jose and Katia
Two other tropical storms have developed since Tuesday morning. Tropical Storm Jose bolted to near-hurricane strength overnight, with top sustained winds of 70 mph as of 11 am Wednesday.
Located about 1100 miles east of the Lesser Antilles, Jose is headed at
17 mph on a steady west-northwest track, steered by the same ridge that
is helping to direct Irma. On its current track, Jose would reach the
northern Leeward Islands by Saturday, but the ridge is predicted to
weaken enough by Saturday to allow Jose to arc just northeast of the
islands. Conditions are favorable for Jose to strengthen into a
hurricane by later Wednesday, and it could approach Category 3 strength
by late in the week. About 25% of the European model ensemble members
bring Jose into the northern Leeward Islands, but all of the GFS
ensemble members keep Jose north of the islands.
Tropical Storm Katia was christened by NHC at 5 am EDT Wednesday, and its estimated top winds had increased to 45 mph as of 11 am EDT.
Located in the Bay of Campeche about 175 miles north of Veracruz,
Mexico, Katia is embedded in a very moist environment with numerous
showers and thunderstorms along and south of a frontal zone (see Figure
9), and the storm’s core has become gradually more organized. NHC
predicts that Katia will become a hurricane by Friday atop the bay’s
very warm waters (30-31°C or 86-88°F). Wind shear will be dropping from
about 10-15 knots to around 5-10 knots by Friday, which also supports
development. Our top track models and the Euro and GFS ensembles are
unanimous in drifting Katia for a couple of days before driving it
southwestward into the Mexican coast this weekend. Extremely heavy rains
of 10 – 20” are possible along parts of the northeast Mexican coast,
especially in northern Veracruz, as Katia approaches and moves
inland.
Dr. Jeff Masters co-wrote this post.
Quote:Video from yesterday's flight in CAT 5 #Irma on #NOAA42. https://t.co/iofV4p56DE has the latest advisories. Credit Rob Mitchell/NOAA pic.twitter.com/IygcNgIbJN
— NOAAHurricaneHunters (@NOAA_HurrHunter) September 6, 2017
If you want Barbuda information Liberty Radio 97.1 in Antigua is about
to give out some information in a few minutes. TuneIn radio has the
station.

HurricaneTracker App‏ @hurrtrackerapp




































If someone is telling you they know where #Irma will make landfall, they're wrong. Florida through the Carolinas are all at risk right now.

















[Image: DJDx8baUMAAyX0_.jpg]
12Z HWRF





[Image: 896875bf7c9a660bca6b54218ad2649b2cc2aa25...&h=629]
Reference URL's