What to Watch Fore(cast) – Sep 20-26

Highlights:

The calm before the storm – This week remains relatively quiet in the tropics as the focus moves to storm formation in the Caribbean. The models are strongly suggesting that the 11-15 day period could be memorable for the U.S. (see the post from 9/19).

The heat continues – The eastern U.S. will be getting very warm temperatures this week, with the warmest temperature anomalies shifting into the western U.S. by the end of the week.

Continual rain in Texas and the Desert Southwest – Rain will be ongoing through most of the week in Texas and parts of the Desert Southwest as an upper-level trough brings a storm system into the region during the second half of the week.

Storm systems slam into the Pacific Northwest – A series of low pressure systems will bring lots of rain and cloud cover to the Pacific Northwest, especially for areas near the coast.

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Discussion:

As Igor and Julia move off to the east and while anything that forms in the East Atlantic this week will stay well to our east, we can take a collective breath before next week’s forecast develops a tropical system or two in the Caribbean. The models have been consistent with developing a storm in the Caribbean that could make landfall on the U.S. in 2-2.5 week’s time. Updates will come as things become clearer.

The eastern U.S. will get a blast of heat over the next few days as a ridge of high pressure in the Southeast draws warm air up into the Mid-Atlantic and Northeast. This heat will subside back to normal temperatures over the weekend as a cold front moves into the Southeast. Parts of the Northeast could receive a good amount of rain from this late-week system, but most of the Mid-Atlantic is supposed to miss out of the much-needed precipitation.

The heat will shift towards the west as an upper-level ridge builds over the region going into the weekend. This burst of heat will bring summer back into the region as we begin the first week of fall, which starts on Wednesday. This heat will be temporary as an upper-level trough pushes into the Pacific NW next week and the ridge shifts back to the east.

Texas and parts of the Desert Southwest will get daily rainfall through mid-week as monsoonal moisture and a low pressure system approaching from the west bring a decent amount of precipitation to the region. Further north in the Pacific Northwest, low pressure systems continue to roll into the region off of the Pacific, bringing clouds and rain into the region throughout the week. The southern and eastern extent of this rainfall will be cut-off not too far inland as the ridge builds into the region over the weekend, but the West Coast could see significant amount of rainfall of 1-4+ inches if the moisture arrives as expected.

Igor bears down on Bermuda as we look into the future

Igor is currently a category 1 hurricane with sustained winds of 85 mph as it slams Bermuda with tropical storm force winds this morning. Don’t let the weakening in wind fool you… the swath of hurricane and tropical storm force winds is so vast that Bermuda will be inundated by Igor for a good 24 hours from the beginning of the event before tropical storm conditions will subside. This is quite a long time for those in the way of a tropical system. Good luck to all those out in Bermuda weathering the storm.

Looking into the future, another tropical wave is trying to form into a tropical system just off the coast of Africa, but this storm is forecast by the models to stay very, very far off to the east. The next real threat to the U.S. could form in the western Caribbean about 8-10 days from now. Both the GFS and ECMWF models have something forming in that area, but the upper-level pattern which would steer the storm is nearly the opposite in the 11-15 day period between these two models, which would greatly affect where this potential storm could make landfall. The only reason why I mention a storm this far out is because of the consistency the models have shown in developing a system in the Caribbean during this time frame, and it stands a chance of making a U.S. landfall. I will continue to monitor the situation with this system, but it remains so far out into the forecast that nothing can be certain.

Karl makes landfall in Mexico as a major hurricane

Major Hurricane Karl broke Bay of Campeche records for being the strongest hurricane that far south into the Bay. Karl came off of the Yucatan Peninsula as a Tropical Storm and quickly spun up over the course of 1.5 days to a category 3 winds, eventually maxing out at sustained winds of 120 mph.

Here’s the official data:

NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL132010
1200 PM CDT FRI SEP 17 2010

…KARL MAKES LANDFALL ON THE SOUTHWEST GULF COAST OF MEXICO…

MEXICAN RADAR OBSERVATIONS AND SATELLITE IMAGES INDICATE THAT THE
CENTER OF HURRICANE KARL MADE LANDFALL ON THE SOUTHWEST COAST OF
MEXICO ABOUT 10 MILES…15 KM…NORTH OF VERACRUZ MEXICO NEAR 1130
AM CDT…1630 UTC. THE MAXIMUM SUSTAINED WINDS AT LANDFALL WERE
ESTIMATED TO BE 115 MPH…185 KM/HR.

SUMMARY OF 1130 AM CDT…1630 UTC…INFORMATION
————————————————–
LOCATION…19.3N 96.2W
ABOUT 10 MI…15 KM N OF VERACRUZ MEXICO
MAXIMUM SUSTAINED WINDS…115 MPH…185 KM/HR
PRESENT MOVEMENT…WSW OR 255 DEGREES AT 8 MPH…13 KM/HR
MINIMUM CENTRAL PRESSURE…976 MB…29.82 INCHES

Initial readings near the core reported weaker winds when the eye came ashore around 12:30pm EDT, so further analysis will have to be done for sure. It was definitely a unique and interesting hurricane.

Mid-Atlantic Discussion – September 16

A shortwave trough will be packing a big punch of energy as it moves east over the Mid-Atlantic region. In the high shear/low CAPE category, this system has plenty of upper-level support from a vort. max and the left-exit region of a developing upper-level jet. A strong 850mb jet will also be developing this morning and afternoon, which will provide nice bulk shear values in WV and W PA. This low-level jet will also rapidly transport 60s dewpoints into the region, which will help fuel storms as they initiate west of the Appalachians.

Visible satellite and radar looks rather poor this morning, with widespread cloud cover and precipitation in OH, WV and W PA. However, given the good amount of upper-level support and orographic lift from the Appalachians, storms could still fire soon after the rain passes through. Water vapor looks favorable for dry-slot initiation, which can be rather potent with the upper-level support. This would lead me to generally agree with the SPC forecast with the overall severe risks.

There is also a risk for severe weather near the East Coast as unstable air moves in off the Atlantic, but it will not have as much support from the upper-level features, so it will have to rely more on daytime heating to initiate storms.

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Chase potential: 60% (would be higher if travel distance was shorter)

Chase target(s):
WV/W PA
DELMARVA/NJ

T.S. Karl hits the Yucatan as it tries to get back to water

Tropical Storm Karl made landfall on the Yucatan Peninsula earlier today as it continues its WNW movement towards the East Pacific. Karl will move over the Bay of Campeche tomorrow and is expected to rapidly intensify before making landfall in central Mexico. Karl stands a good chance of making it to a category 1 hurricane before its second landfall… a feat it almost accomplished this morning as it hit the Yucatan as a strong tropical storm.

Here’s some Karl awesomeness for you all… still a very nice structure despite now having spent about 10 hours over land (taken at 5:45pm EDT).

Igor and Julia continue to chug away in the Atlantic as both weaken slightly from their maximum winds they achieved earlier today. No U.S. landfall should come from any of these storms, but models are strongly hinting at a storm (or two) that could impact the U.S. towards the end of the month.

T.S. Karl forms as Igor tries to go cat. 5

Tropical Storm Karl has formed in the western Caribbean as of 5:00pm ET, and it is forecast to head WNW towards the Yucatan Peninsula, making landfall there sometime tomorrow before sliding into the Bay of Campeche. Once off the Yucatan, Karl will have the opportunity to strengthen into a hurricane before making landfall again in northern/central Mexico early this weekend. Karl is not expected to make landfall on U.S. soil, but clouds and rain associated with the tropical system could impact Texas as it meanders into the East Pacific.

Igor is re-intensifying tonight following a period of weakening, and has another shot at becoming a category 5 hurricane. If successful, Igor will be the first Atlantic Basin category 5 hurricane since Dean and Felix in 2007. Dean had the most impressive center of low pressure at 907 mb, while Felix bottomed-out at 930mb. This year, Earl hit 928 mb as it peaked as a category 4 hurricane, and Igor is currently at its peak of 933 mb with wind speeds of 145 mph.

Not to be outdone, Julia continues to slowly strengthen, and it is currently a category 1 hurricane with wind speeds of 85 mph. Julia has not been talked about much since it is shadowed by the powerful Igor and the practically-imminent landfalls of Karl. Julia is expected to recurve much further east than Igor, and it should not pose any huge threat to land.

IR Satellite:

What to Watch Fore(cast) – Sep 13-19

Highlights:

Tropics in full gear – Igor is a strong category 4 hurricane in the central Atlantic, with Tropical Storm Julia further to the east. There is another area of interest in the Caribbean, which could form into a named system later this week.

Variable weather in the East – A disturbed weather pattern will bring several shots of wet weather into the Northeast and northern Mid-Atlantic.

Heat cranks away in the South – An area of high pressure will keep the South above normal throughout the week as the summer heat continues.

Cool air working into the northern Plains – A low pressure system diving south from northern Canada will bring below normal temperatures into the northern Plains through most of the week.

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Discussion:

Igor is continuing its westward track early this week as it gets ready to recurve to the north and east during the second half of the week. It will continue to be a major hurricane through the first half of the week, but its strength will be in question during the second half of the week depending on how quickly it moves north. The current forecast will keep Igor well away from the U.S. coastline, but I wouldn’t be surprised if Igor ended up a bit further west than expected (though it would still be offshore). Julia is currently near the Cape Verde Islands and is expected to stay east of Igor throughout it’s lifespan, eventually recurving into the North-Central Atlantic.

A series of low pressure systems will bring cooler conditions overall to the Northeast as rain and afternoon thunderstorms roll across the Northeast and Mid-Atlantic today and during the second half of the week. These systems will entrain cold air down from northern Canada into the northern Plains during the second half of the week. Fall is coming to the North!

Meanwhile, a sub-tropical high is parked over the southern U.S., and it will keep most of the South, from the Desert Southwest to the Southeast, under warm temperature anomalies throughout the week. Areas along the Gulf of Mexico that experience onshore flow will have closer to normal temperatures.