Tropical Depression Fifteen forms in the Caribbean
Tropical Depression Fifteen is here, and is destined to become Tropical Storm Matthew by late this afternoon or this evening. An Air Force hurricane hunter aircraft left the storm near 2pm EDT this afternoon, and on their final pass through the strong northeast quadrant of the storm, found a substantial area of surface winds of 40 - 45 mph with their SFMR instrument. Top flight level winds at 500 feet were 48 mph. These winds support upgrading TD 15 to Tropical Storm Matthew. Satellite loops show that TD 15's heavy thunderstorm activity continues to increase in intensity and areal coverage, with several respectable low-level spiral bands in evidence. There is some dry air to the northwest of TD 15, but it is currently not significantly affecting development.
Figure 1. TD 15 at 11:50am EDT 9/23/10, as seen by NASA's Terra satellite.
Forecast for TD 15
An upper-level high pressure system lies to the west of TD 15, near the coast of Nicaragua. The clockwise flow of air around this high will bring a moderate 10 - 20 knots of wind shear over TD 15 today and Friday. There is some dry continental air lying to the northwest of TD 15, and this shear may be able to drive dry air into the storm, slowing intensification and keeping TD 15 below hurricane strength through Saturday morning. By Saturday afternoon, TD 15 will move more underneath this upper-level high, causing the shear to decline. The SHIPS model forecasts that shear will fall to the low range, 5 - 10 knots, Saturday through Monday. This drop in shear should allow for intensification of TD 15 into a hurricane, if the center stays more than 50 miles offshore.
The future track and intensity of TD 15 depends critically upon the storm's interaction with land over the coming days. If TD 15 misses making landfall in Nicaragua and Honduras, and instead skirts the north coast of Honduras, the storm is likely to intensify into a hurricane by Sunday, as indicated in the official NHC forecast. However, if TD 15 spends significant time over or barely offshore of Honduras, the storm will likely stay below hurricane strength. TD 15 is being forced just north of due west by a strong ridge of high pressure. This ridge will keep the storm moving at 15 mph through Saturday. On Sunday, a trough of low pressure diving southwards over the Eastern U.S. will weaken the steering currents over the Western Caribbean and cause TD 15 to slow and turn more to the north. TD 15 will begin a period of slow and erratic movement on Sunday that may last many days, as the storm wanders in the Western Caribbean and over Belize, Honduras, and Mexico's Yucatan Peninsula. If the center of TD 15 spends significant time over water, the storm could easily develop into powerful and dangerous Hurricane Matthew. If the center remains mostly over land, TD 15 will still generate extremely heavy rains over Central America, but remain below hurricane strength. By late next week, the trough of low pressure over the Eastern U.S. may lift out, allowing a ridge of high pressure to build in and force TD 15 westwards across the Yucatan Peninsula and into the Gulf of Mexico's Bay of Campeche. Alternatively, the trough of low pressure over the Eastern U.S. may amplify, drawing TD 15 northwards across Western Cuba and into Florida. A complicating factor may be the development of a new tropical depression in the Central Caribbean 6 - 8 days from now, as predicted by both the GFS and NOGAPS models with their latest 12Z (8am EDT) runs. The uncertainties in the long-range fate of TD 15 are high, and depend strongly on slight variations in its track that determine how much time the storm spends over land. One thing that is virtually certain is that TD 15 will generate very heavy rains over Nicaragua, Honduras, Belize, and Mexico's Yucatan Peninsula Friday through Tuesday that will cause dangerous flooding rains and life-threatening mudslides.
Tropical Depression Lisa
Tropical Depression Lisa continues to churn the waters of the far Eastern Atlantic. By Saturday night, upper level winds out of the west are expected to increase, bringing high wind shear of 20 - 45 knots over Lisa. The high shear may be capable of destroying the storm by early next week. It appears unlikely that Lisa will affect any land areas.
Elsewhere in the tropics
The remnants of Hurricane Julia are still spinning over the far Eastern Atlantic, and are generating some sporadic heavy thunderstorm to the north of the center of circulation. Julia's remains are being given a 10% chance of re-developing by NHC.
Hurricane Karl's moisture causing flooding in Minnesota, Wisconsin
A plume of very moist air associated with what was Hurricane Karl last week has surged northwards over the Central U.S. over the past two days. This moisture is now being lifted over a warm front draped over Minnesota and Wisconsin, and has generated flooding rains in excess of six inches in southern Minnesota this afternoon. Flood warnings and flood watches are posted for a wide swath of the upper Midwest today, including most of southern Minnesota, northern Wisconsin, and Michigan's Upper Peninsula. These types of rain events are called Predecessor Rain Events (PREs), because they typically precede the actual arrival of the rain shield of a tropical storm.
Figure 2. Radar estimated rainfall over Minnesota.
Next post
I'll have an update on TD 15 Friday morning.
Jeff Masters
Neighbors help a driver to move his vehicle from the flood waters
Reader Comments
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The 850MB level to the surface is very moist now and the 250MB-700MB level is also moistening up.
I feel RI occurring in 12 hrs or so!!!!
Level Geo. Height Air Temp. Dew Point Wind Direction Wind Speed
1007mb (29.74 inHg) Sea Level (Surface) 28.6°C (83.5°F) 24.8°C (76.6°F) 100° (from the E) 26 knots (30 mph)
1000mb 63m (207 ft) 27.8°C (82.0°F) 24.0°C (75.2°F) 95° (from the E) 32 knots (37 mph)
925mb 751m (2,464 ft) 21.8°C (71.2°F) 21.0°C (69.8°F) 110° (from the ESE) 36 knots (41 mph)
850mb 1,483m (4,865 ft) 17.8°C (64.0°F) 17.5°C (63.5°F) 110° (from the ESE) 41 knots (47 mph)
700mb 3,130m (10,269 ft) 10.4°C (50.7°F) Approximately 5°C (41°F) 100° (from the E) 34 knots (39 mph)
500mb 5,860m (19,226 ft) -4.1°C (24.6°F) Approximately -10°C (14°F) 80° (from the E) 35 knots (40 mph)
400mb 7,590m (24,902 ft) -14.3°C (6.3°F) -18.8°C (-1.8°F) 80° (from the E) 29 knots (33 mph)
300mb 9,710m (31,857 ft) -29.7°C (-21.5°F) Approximately -37°C (-35°F) 75° (from the ENE) 28 knots (32 mph)
250mb 10,980m (36,024 ft) -39.3°C (-38.7°F) Approximately -46°C (-51°F) 110° (from the ESE) 21 knots (24 mph)
200mb 12,470m (40,912 ft) -52.5°C (-62.5°F) Reading usually unavailable when air temperature is below -40°C (-40°F) 115° (from the ESE) 17 knots (20 mph)
150mb 14,270m (46,818 ft) Height extrapolated since sonde was released within 25mbs below this level.
13-6-5
We STILL have more to go!
I think your gut doesnt want a hurricane in your backyard.
Go Gut
Probably so. I'm not sure where I'd evacuate to this time. I went to Orlando for Charley. Oops. I may just fly out of state for a few days this time.
LMAO
Now that's just wrong!
I think I'll join ya.
G-IV plane out there right now.
TCDAT5
TROPICAL STORM MATTHEW DISCUSSION NUMBER 2
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL152010
500 PM EDT THU SEP 23 2010
AN AIR FORCE RESERVE RECONNAISSANCE AIRCRAFT INVESTIGATING THE
CYCLONE FOUND 42-KT FLIGHT-LEVEL WINDS AT ABOUT 1500 FT IN THE
NORTHEAST QUADRANT ON ITS OUTBOUND LEG. THAT WIND SPEED WOULD
NORMALLY EQUATE TO ABOUT 34 KT AT THE SURFACE. ALSO...THERE WERE
SEVERAL BELIEVABLE SFMR SURFACE WINDS OF 35-37 KT IN THAT AREA.
SINCE THOSE WIND REPORTS...CONVECTIVE BANDING HAS CONTINUED TO
INCREASE AND BECOME BETTER ORGANIZED..AND THE DEPRESSION HAS BEEN
UPGRADED TO TROPICAL STORM MATTHEW.
THE INITIAL MOTION ESTIMATE IS 280/14. TROPICAL STORM MATTHEW IS
EXPECTED TO MOVE WEST TO WEST-NORTHWESTWARD FOR THE NEXT 48 HOURS
OR SO...AND PASS OVER OR NEAR THE NORTHERN COASTS OF NICARAGUA AND
HONDURAS IN 36-48 HOURS. AFTER THAT...THE GLOBAL MODELS DIFFER ON
THE TIMING OF THE WEAKENING OF THE SUBTROPICAL RIDGE OVER THE
NORTHWESTERN CARIBBEAN SEA AND THE GULF OF MEXICO. A STRONG
MID-LATITUDE TROUGH CURRENTLY OFF THE U.S. WEST COAST IS FORECAST
TO MOVE QUICKLY EASTWARD INTO THE CENTRAL U.S. BY DAY 3...THE
TROUGH IS FORECAST TO DIG SOUTHEASTWARD AND AMPLIFY INTO A LOW
PRESSURE SYSTEM OVER THE SOUTHEASTERN U.S. AND THE GULF OF MEXICO.
EROSION OF THE SUBTROPICAL RIDGE TO THE NORTH OF MATTHEW IS
EXPECTED TO CAUSE THE STEERING CURRENTS TO COLLAPSE ACROSS THE
NORTHWESTERN CARIBBEAN SEA AND THE YUCATAN PENINSULA. ALL OF THE
NHC MODELS ARE CONSISTENT ON THE EVOLUTION OF THIS SYNOPTIC
SCALE PATTERN...EXCEPT FOR THE TIMING. THE GFS...ECMWF...NOGAPS...
HWRF...AND GFDL MODELS KEEP THE LOW WEST OF 85W LONGITUDE BY 120
HOURS...WHEREAS THE UKMET IS MUCH MORE PROGRESSIVE AND MOVES THE
LARGE TROUGH EAST OF 80W. GIVEN THE USUAL SLOW MOVEMENT OF SUCH
A HIGH AMPLITUDE TROUGH...THE UKMET IS CONSIDERED AN OUTLIER MODEL
AT THIS TIME. AS A RESULT...THE OFFICIAL FORECAST TRACK IS A BLEND
OF THE GLOBAL AND REGIONAL MODELS...EXCLUDING THE UKMET SOLUTION...
AND IS JUST AN UPDATE OF THE PREVIOUS FORECAST TRACK.
STEADY INTENSIFICATION IS EXPECTED THROUGH 72 HOURS SINCE MATTHEW
WILL BE MOVING OVER 30C SSTS AND BENEATH A REGION OF UPPER-LEVEL
ANTICYCLONIC FLOW. MATTHEW IS EXPECTED TO MOVE OVER OR NEAR THE
NORTH COAST OF HONDURAS IN 36-48 HOURS...AND MOVE INLAND NEAR
BELIZE BY DAY 4. LAND INTERACTION WOULD DISRUPT THE INTENSIFICATION
PROCESS DESPITE THE OTHERWISE FAVORABLE ENVIRONMENTAL CONDITIONS.
HOWEVER...IF THE CYCLONE REMAINS OVER WATER...THEN MATTHEW COULD
EASILY REACH HURRICANE STRENGTH DURING THE NEXT 48 HOURS AND
BEYOND. THE OFFICIAL INTENSITY FORECAST IS SIMILAR TO THE PREVIOUS
ADVISORY AND THE SHIPS/LGEM MODELS...AND IS BASED ON THE ASSUMPTION
THAT MATTHEW WILL MOVE INLAND AFTER 72 HOURS.
FORECAST POSITIONS AND MAX WINDS
INITIAL 23/2100Z 14.0N 76.9W 35 KT
12HR VT 24/0600Z 14.4N 78.9W 40 KT
24HR VT 24/1800Z 15.1N 81.7W 50 KT
36HR VT 25/0600Z 15.6N 84.0W 60 KT...INLAND
48HR VT 25/1800Z 16.2N 85.8W 60 KT...OVER WATER
72HR VT 26/1800Z 17.1N 88.0W 70 KT
96HR VT 27/1800Z 18.3N 88.4W 70 KT...INLAND
120HR VT 28/1800Z 19.5N 87.5W 70 KT...INLAND
$$
FORECASTER STEWART
Thanks for the math lesson...Learn something new every day!
Dr. M will have a new blog by tomorrow morning.
WTNT45 KNHC 232051
TCDAT5
TROPICAL STORM MATTHEW DISCUSSION NUMBER 2
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL152010
500 PM EDT THU SEP 23 2010
AN AIR FORCE RESERVE RECONNAISSANCE AIRCRAFT INVESTIGATING THE
CYCLONE FOUND 42-KT FLIGHT-LEVEL WINDS AT ABOUT 1500 FT IN THE
NORTHEAST QUADRANT ON ITS OUTBOUND LEG. THAT WIND SPEED WOULD
NORMALLY EQUATE TO ABOUT 34 KT AT THE SURFACE. ALSO...THERE WERE
SEVERAL BELIEVABLE SFMR SURFACE WINDS OF 35-37 KT IN THAT AREA.
SINCE THOSE WIND REPORTS...CONVECTIVE BANDING HAS CONTINUED TO
INCREASE AND BECOME BETTER ORGANIZED..AND THE DEPRESSION HAS BEEN
UPGRADED TO TROPICAL STORM MATTHEW.
THE INITIAL MOTION ESTIMATE IS 280/14. TROPICAL STORM MATTHEW IS
EXPECTED TO MOVE WEST TO WEST-NORTHWESTWARD FOR THE NEXT 48 HOURS
OR SO...AND PASS OVER OR NEAR THE NORTHERN COASTS OF NICARAGUA AND
HONDURAS IN 36-48 HOURS. AFTER THAT...THE GLOBAL MODELS DIFFER ON
THE TIMING OF THE WEAKENING OF THE SUBTROPICAL RIDGE OVER THE
NORTHWESTERN CARIBBEAN SEA AND THE GULF OF MEXICO. A STRONG
MID-LATITUDE TROUGH CURRENTLY OFF THE U.S. WEST COAST IS FORECAST
TO MOVE QUICKLY EASTWARD INTO THE CENTRAL U.S. BY DAY 3...THE
TROUGH IS FORECAST TO DIG SOUTHEASTWARD AND AMPLIFY INTO A LOW
PRESSURE SYSTEM OVER THE SOUTHEASTERN U.S. AND THE GULF OF MEXICO.
EROSION OF THE SUBTROPICAL RIDGE TO THE NORTH OF MATTHEW IS
EXPECTED TO CAUSE THE STEERING CURRENTS TO COLLAPSE ACROSS THE
NORTHWESTERN CARIBBEAN SEA AND THE YUCATAN PENINSULA. ALL OF THE
NHC MODELS ARE CONSISTENT ON THE EVOLUTION OF THIS SYNOPTIC
SCALE PATTERN...EXCEPT FOR THE TIMING. THE GFS...ECMWF...NOGAPS...
HWRF...AND GFDL MODELS KEEP THE LOW WEST OF 85W LONGITUDE BY 120
HOURS...WHEREAS THE UKMET IS MUCH MORE PROGRESSIVE AND MOVES THE
LARGE TROUGH EAST OF 80W. GIVEN THE USUAL SLOW MOVEMENT OF SUCH
A HIGH AMPLITUDE TROUGH...THE UKMET IS CONSIDERED AN OUTLIER MODEL
AT THIS TIME. AS A RESULT...THE OFFICIAL FORECAST TRACK IS A BLEND
OF THE GLOBAL AND REGIONAL MODELS...EXCLUDING THE UKMET SOLUTION...
AND IS JUST AN UPDATE OF THE PREVIOUS FORECAST TRACK.
STEADY INTENSIFICATION IS EXPECTED THROUGH 72 HOURS SINCE MATTHEW
WILL BE MOVING OVER 30C SSTS AND BENEATH A REGION OF UPPER-LEVEL
ANTICYCLONIC FLOW. MATTHEW IS EXPECTED TO MOVE OVER OR NEAR THE
NORTH COAST OF HONDURAS IN 36-48 HOURS...AND MOVE INLAND NEAR
BELIZE BY DAY 4. LAND INTERACTION WOULD DISRUPT THE INTENSIFICATION
PROCESS DESPITE THE OTHERWISE FAVORABLE ENVIRONMENTAL CONDITIONS.
HOWEVER...IF THE CYCLONE REMAINS OVER WATER...THEN MATTHEW COULD
EASILY REACH HURRICANE STRENGTH DURING THE NEXT 48 HOURS AND
BEYOND. THE OFFICIAL INTENSITY FORECAST IS SIMILAR TO THE PREVIOUS
ADVISORY AND THE SHIPS/LGEM MODELS...AND IS BASED ON THE ASSUMPTION
THAT MATTHEW WILL MOVE INLAND AFTER 72 HOURS.
FORECAST POSITIONS AND MAX WINDS
INITIAL 23/2100Z 14.0N 76.9W 35 KT
12HR VT 24/0600Z 14.4N 78.9W 40 KT
24HR VT 24/1800Z 15.1N 81.7W 50 KT
36HR VT 25/0600Z 15.6N 84.0W 60 KT...INLAND
48HR VT 25/1800Z 16.2N 85.8W 60 KT...OVER WATER
72HR VT 26/1800Z 17.1N 88.0W 70 KT
96HR VT 27/1800Z 18.3N 88.4W 70 KT...INLAND
120HR VT 28/1800Z 19.5N 87.5W 70 KT...INLAND
$$
FORECASTER STEWART
This will help for sure.
AT THIS TIME. AS A RESULT...THE OFFICIAL FORECAST TRACK IS A BLEND
OF THE GLOBAL AND REGIONAL MODELS...EXCLUDING THE UKMET SOLUTION...
AND IS JUST AN UPDATE OF THE PREVIOUS FORECAST TRACK."
"THE AREA IS STILL ON TRACK TO SEE A COLD
FRONT MOVE THROUGH THE AREA SOME TIME SUNDAY AFTERNOON THROUGH SUNDAY
NIGHT. EXPECT DECREASING RAIN CHANCES BEGINNING LATE SUNDAY AFTERNOON
UP NORTH...AND THEN AREA WIDE SUNDAY NIGHT THROUGH EARLY MONDAY MORNING.
A NORTHERLY FLOW AT THE SURFACE AND ALOFT IS ANTICIPATED FOR MUCH OF
NEXT WEEK...AND THIS PATTERN WILL BRING COOLER TEMPERATURES (ESPECIALLY
WITH OVERNIGHT LOWS) TO THE ENTIRE AREA. THE COMBINATION OF A REINFORCING
FRONT OR TWO AND THE CIRCULATION AROUND NEWLY FORMED TROPICAL DEPRESSION
FIFTEEN (LIKELY SOON TO BE BECOME TROPICAL STORM AND POTENTIALLY HURRICANE
MATTHEW) COULD POSSIBLY KEEP A VERY DRY FLOW ACROSS SOUTHEAST TEXAS
THROUGH THE END OF NEXT WEEK AND ON INTO NEXT WEEKEND. HELLO FALL!"
Matthew, "one for the history" save this.
Not exactly, but sorta some people consider it a language others a dialect of english, it is really quite hard to explain without going on for ever. Best way to describe it is a heavy accent on the vowels, often with an extra vowle thrown in for the heck of it. It would make an enghlish teacher cringe, because it is close enough that you would think it is just someone with really bad linguisitc skils, if you did not know about the "dialect"
and Pensacola is cashews.
2008 didn't have 'Marco' until October 6th.
2007 didn't have 'Melissa' until September 28th.
Those seasons had 16 and 15 named storms respectively. Given that we're at Matthew on September 23rd says that we'll top 17-18 named.
1) With Matthew, we've now seen ten storms named in a 33-day span, beating the 35-day span in 1995 that saw the same number of storms named.
2) We now have the same number of named storms 1995 did on this date, and that season, you may remember, ended with 20 named storms.
3) This is the 32nd day out of the last 33 with at least one named storm, and the 20th with at least two named storms.
Has a good initialization and track is that of NHC but keep the center offshore before turning N to NE.
Amazing the wakes of a storm can be followed just by SST
What is RIDGES?
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