Written by Sig Silber
This Article has been updated. You can access the updated article at: Turks and Caicos Islands Next – 22Sep2017
11:30 AM EDT Sept 21, 2017: LATEST FROM NHC: “MARIA HEADING TOWARD THE TURKS AND CAICOS ISLANDS… …HEAVY RAINFALL AND FLOODING CONTINUES IN PUERTO RICO AND THE DOMINICAN REPUBLIC…” “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”.
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Damage Reports from the recent impacts of Hurricane Maria start to trickle in. Here is one. And here is an impact assessment and analysis. This report is focused on Puerto Rico. Our coverage on impacts will expand as more information becomes available.
This is an active period in the tropics so we are starting with the overview of the situation in both the Pacific and the Atlantic even though right now only the Pacific presents major threats. Those potentially impacted by any of these storms should consult their local sources of information. The Public Advisories and other information that is available from the NOAA National Hurricane Center can be found here. Information from the Weather Prediction Center can be found here.
First the Atlantic
More Detail
And now the Pacific.
We start our Report with Hurricane Maria. The”M” Designation means a very powerful storm: Category 3 or higher.
And the Discussion
Hurricane Maria Discussion Number 22 NWS National Hurricane Center Miami FL 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.
KEY MESSAGES:
1. Flash flood emergencies continue in portions of Puerto Rico due to persistent heavy rainfall from Maria’s trailing rainbands. Catastrophic flooding is occurring on the island, especially in areas of mountainous terrain, and everyone in Puerto Rico should continue to follow advice from local officials to avoid these life-threatening flooding conditions.
2. A Hurricane Warning is in effect for the northern coast of the Dominican Republic, the Turks and Caicos Islands, and the southeastern Bahamas, where Maria is expected to bring dangerous wind, storm surge, and heavy rainfall.
FORECAST POSITIONS AND MAX WINDS
INIT 21/1500Z 20.2N 69.1W 100 KT 115 MPH
12H 22/0000Z 21.0N 69.9W 105 KT 120 MPH
24H 22/1200Z 22.2N 70.7W 105 KT 120 MPH
36H 23/0000Z 23.6N 71.4W 100 KT 115 MPH
48H 23/1200Z 25.1N 71.9W 95 KT 110 MPH
72H 24/1200Z 28.2N 72.3W 95 KT 110 MPH
96H 25/1200Z 30.5N 71.5W 85 KT 100 MPH
120H 26/1200Z 33.0N 70.0W 75 KT 85 MPH
Here is the current Track Map for Jose.
Jose Discussion
Tropical Storm Jose Discussion Number 65 NWS National Hurricane Center Miami FL 1100 AM AST Thu Sep 21 2017
Satellite and radar data suggest that Jose is gradually spinning down. The convective bands are relatively shallow, except over the western quadrants where the cloud tops are a bit colder. The outer-most bands are very near the offshore islands of southeastern New England, where there have been reports of tropical-storm-force winds, especially in gusts. The Air Force Hurricane Hunters investigated Jose earlier this morning, and a combination of the flight-level winds, SFMR observations, and dropsonde data support holding the initial intensity at 50 kt.
The intensity forecast appears straightforward. Cool waters, dry air, and an expected increase in wind shear should cause Jose to steadily weaken and lead to post-tropical transition within the next 24 hours. The post-tropical system is predicted to degenerate into a trough by day 4, as suggested by the GFS and ECMWF models. The NHC intensity forecast is just an update of the previous one, and it lies close to the consensus models.
As previously predicted, Jose has become stationary. Since the storm is expected to remain in weak steering currents for the next few days, Jose is forecast to meander off the coast of southeastern New England until it dissipates. This track prediction is not too different from the previous one, and it lies near the middle of the guidance.
KEY MESSAGES:
1. Tropical-storm-force winds, especially in gusts, are occurring within the tropical storm warning area. These conditions are expected to continue through tonight.
2. Minor coastal flooding is possible along portions of the coast of southern New England during the next few days. Please see products issued by local National Weather Service forecast offices.
3. Swells generated by Jose are affecting Bermuda and much of the U.S. east coast, and will likely cause dangerous surf and rip current conditions for the next few days in these areas.
FORECAST POSITIONS AND MAX WINDS
INIT 21/1500Z 39.6N 68.2W 50 KT 60 MPH
12H 22/0000Z 39.5N 68.3W 45 KT 50 MPH
24H 22/1200Z 39.6N 68.9W 40 KT 45 MPH…POST-TROPICAL
36H 23/0000Z 39.5N 69.2W 40 KT 45 MPH…POST-TROPICAL
48H 23/1200Z 39.4N 69.3W 35 KT 40 MPH…POST-TROPICAL
72H 24/1200Z 39.1N 68.0W 30 KT 35 MPH…POST-TROP/REMNT LOW
96H 25/1200Z…DISSIPATED
General Weather Situation
We believe that it is easier to understand what is going on with individual storms if they are put into the context of the overall weather situation.
Some of the graphics below show the two storms of most interest.
Additional Graphics
This is a national animation of weather fronts and precipitation forecasts with four 6-hour projections of the conditions that will apply covering the next 24 hours and a second day of two 12-hour projections the second of which is the forecast for 48 hours out and to the extent it applies for 12 hours, this animation is intended to provide coverage out to 60 hours. This graphic is very relevant as one can see both storms of most interest in this graphic. .