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WxWatcher007

Major Hurricane Laura

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Does the disruption of Laura's core also lead to a larger circulation?

This would be a problem to hinder Laura if it were already a large hurricane i.e. Ike or Georges with an expansive windfield and wide pressure gradients prior to riding the length of Cuba's spine. But Laura is still a Tropical Storm with a relatively weak region of pressure gradient and RMW with a 990s hPa surface low. Expansive extension of gradients cannot occur unless Laura deepens its central pressure significantly. Then the overall low pressure gradients could expand out from the cyclone making it difficult for rapid reintensification. Laura has yet to go through initial deepening so pretty much if it can exit Cuba with a decent structure and intact vortex, it could still rapidly intensify as a tight cyclone. If it were to traverse the NW Caribbean paralleling the southern Cuba coastline, it could hypothetically deepen rapidly prior to a second Cuba landfall. Who knows then...all is speculation.
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8 minutes ago, Superstorm93 said:

Looks like we might get an actual center fix from recon soon if this doesn't move inland

Looks like it's making landfall in Cuba. This thing has proven again to not be a coast hugger, just plowing WNW. Recon data will help either way. 

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2 minutes ago, Superstorm93 said:

Extrapolated pressures down to 998mb with peak SFMR winds around 48 knots just west of the 18z position. 

Looks like the center is SE of Guantanamo.

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Center is still dreadfully disorganized per recon. Probably a godsend for the eventual prospects of the storm, as the higher-terrain of Cuba likely won’t have as much of a destructive impact on a disorganized storm vs an organized storm. 

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This is the last recon position overlayed on the 15z (initial) and 00z forecasts. Recon center is a bit south of the NHC position. It's still far enough north that I think it will make landfall in Cuba, though. Direction is about 280 degrees. 

Short_Term_Motion.PNG

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12z HWRF. Track passes over Cuba at least twice, then explodes in the Gulf. Peak intensity is 138kts before land interaction.

hwrf_mslp_wind_13L_30.png

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33 minutes ago, FLweather said:

The GEFS is weird too. 

Marco doesn't even really make landfall in LA. Like it hits a brick wall. Then starts heading west towards TX. Eventually loosing Marco and Laura absorbs what's left. Before making landfall in Tx.

Crazy 2020 crap .

 

gfs-ens_mslpaNorm_us_9.pnggfs-ens_mslpaNorm_us_10.png

gfs-ens_mslpaNorm_us_14.png

If Macro gets sheared, it will likely turn more W with the low-level flow.  18z SHIPS output has 29 kt of shear over Macro at 06z Mon and it steadily increases after that.  15 kt of shear initialized 18z today.

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I still find it funny the next storm name is Nana.  That’s not even a name, thats a nickname.  If that ends up a long tracker social media is going to be a joke fest for two weeks 

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6 minutes ago, NJwx85 said:

12z HWRF. Track passes over Cuba at least twice, then explodes in the Gulf. Peak intensity is 138kts before land interaction.

hwrf_mslp_wind_13L_30.png

Distressingly close to the Houston metro

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2 hours ago, Superstorm93 said:

Radar supports visible sat as well 

bf41852100f7abd34616a33d6c18b7f6.gif

The peaks on the southern coast of Cuba could keep Laura in check even over the water disrupting banding maybe?  We shall see between now and say 8 pm est. 

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It's been extremely hot here in the 'calm before the storm', where the air on the outer periphery is subsiding. Heat index hit 112! Must be some sort of record. Even with a solid east breeze it is scorching out there. 

Anyways, all that heat is about to end, outer squall lines got strong enough to break through subsidence cap and should be here in 1-2 hours. Probably will be quite exciting weather. CAPE is tremendous, and also lots of helicity. Could make for some severe weather. 

Screen Shot 2020-08-23 at 3.33.36 PM.png

GOES19262020236RQgohB.jpg

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Some pretty froggy winds from that drop off the far eastern tip of Cuba.  Generally out of the ESE-SE .  She's still doing a hula dance....


Significant Wind Levels
Level    Wind Direction    Wind Speed
1007mb (Surface)     100° (from the E)     31 knots (36 mph)
1004mb     95° (from the E)     37 knots (43 mph)
989mb     100° (from the E)     44 knots (51 mph)
968mb     105° (from the ESE)     42 knots (48 mph)
957mb     105° (from the ESE)     47 knots (54 mph)
940mb     110° (from the ESE)     45 knots (52 mph)
920mb     120° (from the ESE)     56 knots (64 mph)
912mb     125° (from the SE)     55 knots (63 mph)
886mb     125° (from the SE)    66 knots (76 mph)
879mb     130° (from the SE)     59 knots (68 mph)
850mb     140° (from the SE)     63 knots (72 mph)
796mb     150° (from the SSE)     49 knots (56 mph)
748mb     135° (from the SE)     34 knots (39 mph)
697mb     130° (from the SE)     35 knots (40 mph)
 

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9 minutes ago, Jackstraw said:

Some pretty froggy winds from that drop off the far eastern tip of Cuba.  Generally out of the ESE-SE .  She's still doing a hula dance....


Significant Wind Levels
Level    Wind Direction    Wind Speed
1007mb (Surface)     100° (from the E)     31 knots (36 mph)
1004mb     95° (from the E)     37 knots (43 mph)
989mb     100° (from the E)     44 knots (51 mph)
968mb     105° (from the ESE)     42 knots (48 mph)
957mb     105° (from the ESE)     47 knots (54 mph)
940mb     110° (from the ESE)     45 knots (52 mph)
920mb     120° (from the ESE)     56 knots (64 mph)
912mb     125° (from the SE)     55 knots (63 mph)
886mb     125° (from the SE)    66 knots (76 mph)
879mb     130° (from the SE)     59 knots (68 mph)
850mb     140° (from the SE)     63 knots (72 mph)
796mb     150° (from the SSE)     49 knots (56 mph)
748mb     135° (from the SE)     34 knots (39 mph)
697mb     130° (from the SE)     35 knots (40 mph)
 

That plus 70 mph flight level winds off NE coast of Cuba, plus satellite imagery, seems to suggest the real center may be just off the northern coast of Cuba. Especially since that weak low level feature they found will be smashed by the mountains. 

In official terms, this is what they would call an elongated circulation, and it's been like this since Puerto Rico. 

Zooming out, could Hurricane Marco being stronger and further NE than expected cause Laura to go a little bit more north as well? We will see. NWS Miami speculated that yesterday. Basically, the further east Marco ends up, and the stronger it is, the less strong the steering ridge is. 

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16 minutes ago, SnowGoose69 said:

I still find it funny the next storm name is Nana.  That’s not even a name, thats a nickname.  If that ends up a long tracker social media is going to be a joke fest for two weeks 

We shall see how nice and sweet grandma really is. 

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This is the convergence zone I was speculating about last night, between Marco and Laura. The circulation of Laura is now colliding with the circulation of Marco, leading to an area of potential severe weather with intense downpours, tropical storm force gusts, and potential tornadoes (helicity profile is perfect with easterly winds at low level backing to southerly as you go up). 

Also, it is coming inland during a very hot day in Florida, so tons of CAPE.

Basically this is not just a regular outer band. It's being enhanced by convergence between Marco and Laura, and this convergence is powerful enough to lift parcels through a strong subsidence inversion. 

Screen_Shot_2020-08-23_at_3_55.12_PM.png

EDIT: NWS Miami discussion is juicy 

Rest of Today and Tonight...

High pressure ridge over the western Atlantic with breezy east-
southeasterly flow across the region. Scattered showers and
thunderstorms possible mainly over the interior and west coast
region this afternoon. However, overall coverage may be limited as
there is some drier air seen in the 18Z MFL sounding that has
moved in across the region this afternoon.

Even though convection is limited, there is plenty of instability
over western portions of the area where an isolated strong
thunderstorm will be possible this afternoon. CAPE values with
daily heating will approach ~3000 J/kg and DCAPE of ~900 J/kg. SRH
also encroaching upon 90-100 m2/s2. Main hazards this afternoon
will be strong wind gusts reaching up to 50 mph, funnel clouds,
localized heavy rainfall, and minor flooding in poor drainage
/low- lying areas.

Tonight, gusty showers will be possible over the local waters as the
outflow boundaries and bands may begin to encroach our region.
Breezy conditions and tropical rain showers will be possible
overnight tonight. There will also be deteriorating marine
conditions with increasing seas, swells beginning tonight over the
Atlantic and then Gulf waters.

.Long Term...

Monday And Monday Night...

From the latest NHC forecast advisory Tropical Storm Laura will pass
south of the region with the center passing over or along the
southern coast of Cuba. Although the center will stay south of the
region there will still be indirect impacts across South Florida.
Monday will be gusty with squally tropical rainbands and showers
across the region.

The outer rainbands and squally showers will be possible for much of
the day and night until Laura can move further west into the Gulf of
Mexico. Although sustained tropical storm force winds are not
expected across South Florida, rainbands and squalls will be capable
of producing tropical storm force wind gusts. Repeated rounds of
heavy rain bands/showers may cause localized flooding in isolated
locations. Especially over coastal areas, during high tide, where
elevated tides from the gusty onshore flow may further enhance
flooding potential. Environmental parameters (being in the
Northeast quadrant) such as increased SRH and shear values will
allow the potential for funnel clouds and tornadoes to be possible
across the region.
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11 minutes ago, turtlehurricane said:

That plus 70 mph flight level winds off NE coast of Cuba, plus satellite imagery, seems to suggest the real center may be just off the northern coast of Cuba. Especially since that weak low level feature they found will be smashed by the mountains. 

In official terms, this is what they would call an elongated circulation, and it's been like this since Puerto Rico. 

Zooming out, could Hurricane Marco being stronger and further NE than expected cause Laura to go a little bit more north as well? We will see. NWS Miami speculated that yesterday. Basically, the further east Marco ends up, and the stronger it is, the less strong the steering ridge is. 

are u ****ing kidding me? 

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26 minutes ago, SnowGoose69 said:

I still find it funny the next storm name is Nana.  That’s not even a name, thats a nickname.  If that ends up a long tracker social media is going to be a joke fest for two weeks 

As a Nana, I approve this name  :wub:   :lol:

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The latest 12z HWRF IR simulation has Laura as a Cat 5 just prior to US landfall.  How reliable is the intensity modeling of the HWRF for Gulf storms? 

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7 minutes ago, turtlehurricane said:

This is the convergence zone I was speculating about last night, between Marco and Laura. The circulation of Laura is now colliding with the circulation of Marco, leading to an area of potential severe weather with intense downpours, tropical storm force gusts, and potential tornadoes (helicity profile is perfect with easterly winds at low level backing to southerly as you go up). 

Also, it is coming inland during a very hot day in Florida, so tons of CAPE.

Basically this is not just a regular outer band. It's being enhanced by convergence between Marco and Laura, and this convergence is powerful enough to lift parcels through a strong subsidence inversion. 

Screen_Shot_2020-08-23_at_3_55.12_PM.png

EDIT: NWS Miami discussion is juicy 

Rest of Today and Tonight...

High pressure ridge over the western Atlantic with breezy east-
southeasterly flow across the region. Scattered showers and
thunderstorms possible mainly over the interior and west coast
region this afternoon. However, overall coverage may be limited as
there is some drier air seen in the 18Z MFL sounding that has
moved in across the region this afternoon.

Even though convection is limited, there is plenty of instability
over western portions of the area where an isolated strong
thunderstorm will be possible this afternoon. CAPE values with
daily heating will approach ~3000 J/kg and DCAPE of ~900 J/kg. SRH
also encroaching upon 90-100 m2/s2. Main hazards this afternoon
will be strong wind gusts reaching up to 50 mph, funnel clouds,
localized heavy rainfall, and minor flooding in poor drainage
/low- lying areas.

Tonight, gusty showers will be possible over the local waters as the
outflow boundaries and bands may begin to encroach our region.
Breezy conditions and tropical rain showers will be possible
overnight tonight. There will also be deteriorating marine
conditions with increasing seas, swells beginning tonight over the
Atlantic and then Gulf waters.

.Long Term...

Monday And Monday Night...

From the latest NHC forecast advisory Tropical Storm Laura will pass
south of the region with the center passing over or along the
southern coast of Cuba. Although the center will stay south of the
region there will still be indirect impacts across South Florida.
Monday will be gusty with squally tropical rainbands and showers
across the region.

The outer rainbands and squally showers will be possible for much of
the day and night until Laura can move further west into the Gulf of
Mexico. Although sustained tropical storm force winds are not
expected across South Florida, rainbands and squalls will be capable
of producing tropical storm force wind gusts. Repeated rounds of
heavy rain bands/showers may cause localized flooding in isolated
locations. Especially over coastal areas, during high tide, where
elevated tides from the gusty onshore flow may further enhance
flooding potential. Environmental parameters (being in the
Northeast quadrant) such as increased SRH and shear values will
allow the potential for funnel clouds and tornadoes to be possible
across the region.

Hate to get a little OT. But we had some showers about 30 minutes ago. Nw Orlando. 

The rates were on the heavy side was quite windy. Blowing sheets of rain out of east. Definitely tapping into the stronger winds aloft. 

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On the topic of Laura's position...here is the multi dataset position fix at 18Z from the RAMMB site. That is the eastern tip of Cuba north of the center.

Ab0nmda.gif

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