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No Mesoscale Discussions are in effect as of Sun Oct 22 02:26:02 UTC 2023.

...TAMMY JUST NORTH-NORTHWEST OF BARBUDA... ...CONTINUES TO BRING STRONG WINDS AND HEAVY RAINS OVER PORTIONS OF THE LEEWARD ISLANDS... As of 11:00 PM AST Sat Oct 21 the center of Tammy was located near 17.8, -61.9 with movement NNW at 10 mph. The minimum central pressure was 992 mb with maximum sustained winds of about 85 mph.

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0739 PM CDT Sat Oct 21 2023 Valid 220100Z - 221200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms will not occur through tonight across the contiguous United States. ...Synopsis... Water-vapor imagery early this evening shows a mid-level shortwave trough moving east across southern ID/northern UT and downstream of a larger trough over the eastern Pacific. A few thunderstorms have been observed this evening in association with weak buoyancy/appreciable ascent with the ID/UT disturbance. This activity may linger for a couple of more hours before the zone of stronger ascent moves east into a more dry environment farther east in WY. Elsewhere, tranquil conditions reside over much of the Lower 48 states owing to building surface high pressure over the north-central U.S. and a departing mid-level shortwave trough over New England. ..Smith.. 10/22/2023 Read more

000
ABPZ20 KNHC 212346
TWOEP

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
500 PM PDT Sat Oct 21 2023

For the eastern North Pacific...east of 140 degrees west longitude:

Active Systems:
The National Hurricane Center is issuing advisories on recently
downgraded Tropical Storm Norma, located over the southern tip of
the Baja California peninsula, north of Cabo San Lucas.

South of Southern Mexico (EP91):
A broad area of low pressure located several hundred miles south of
the Gulf of Tehuantepec continues to produce a large area of shower
and thunderstorm activity. The upper-level winds are expected to
become more conducive for development of this system during the next
couple of days, and a tropical depression is likely to form by early
next week. The system is forecast to meander or drift generally
northward through early next week.
* Formation chance through 48 hours...high...70 percent.
* Formation chance through 7 days...high...80 percent.

$$
Forecaster Kelly

000
ABNT20 KNHC 212315
TWOAT

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 PM EDT Sat Oct 21 2023

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

Active Systems:
The National Hurricane Center is issuing advisories on Hurricane
Tammy, located near Antigua.

Southwestern Caribbean Sea:
A broad area of low pressure located over the southwestern
Caribbean Sea continues to produce disorganized showers and
thunderstorms. Some slow development of this system is possible
before it moves inland over Central America by late Monday.
* Formation chance through 48 hours...low...20 percent.
* Formation chance through 7 days...low...20 percent.

$$
Forecaster Pasch

...HEAVY RAINS AND FLASH FLOODING TO CONTINUE THROUGH THE WEEKEND... As of 9:00 PM MDT Sat Oct 21 the center of Norma was located near 23.5, -109.7 with movement NNE at 6 mph. The minimum central pressure was 989 mb with maximum sustained winds of about 65 mph.

Hay production in Mississippi was down at least 28% this year, due to drought. Hay growers usually get three cuttings per year, and often four when conditions are right. “This year, you were truly blessed to get maybe two,” according to a Mississippi State University Extension forage agronomist. “A lot of the second cutting was delayed by quite a bit of rain in June and July. We had drought conditions after that, and although growers kept waiting to get a third cutting, the forage never could get going.” WJTV TV 12 (Jackson, Miss.), Oct 20, 2023

Crop yields were “really down” in Pottawatomie County in northeast Kansas. Some farmers were moving cattle off pastures earlier than usual. Hay production was also poor. The area did not receive any significant precipitation from late July to early October, leaving soybean yields less than half of a normal crop. SF| Successful Farming (Des Moines, Iowa), Oct 20, 2023

Morton pumpkin growers attested that getting seeds to germinate was a challenge, but rain helped the seeds to sprout and grow. Drought reduced the size of the pumpkins and number of the pumpkins, but the dry conditions also led to very little rot among the pumpkins. Peoria Public Radio (Ill.), Oct 13, 2023

Drought caused some apples in Iowa to be ready for picking as much as three weeks earlier than normal. Cherokee Chronicle Times (Iowa), Oct 19, 2023

The Texas A&M Agronomy Society cannot offer its annual corn maze and fall festival this year, due to extreme drought this summer that killed the corn crop. The seeds were planted in July, but no rain fell for nearly three or more months with temperatures above 100°. The seeds were irrigated, but the high soil temperatures caused the water to evaporate, leaving the seeds dry. KBTX (Bryan, Texas), Oct 19, 2023

A burn ban took effect, prohibiting outdoor burning and open fires within city limits, including recreational fires in fire pits. FOX23 News (Tulsa, Okla.), Oct 19, 2023

Drinking water advisories in Plaquemines Parish have been lifted as reverse osmosis machines and barges moving millions of gallons of water were arriving to dilute the salt in the water to safe levels below 250 ppm consistently. FOX 8 (New Orleans, La.), Oct 18, 2023 The water supply for communities drawing water from the Mississippi River is being protected by an underwater barrier to block the progression of a saltwater wedge that is moving upstream since July. The saltwater is expected to overtop the current barrier sometime around Sept. 22. In June, saltwater affected the drinking water of residents in lower Plaquemines Parish, forcing them to use water provided by the parish. About 2,000 people were using the distributed water, and the parish has given out more than 1.5 million gallons of water. If the saltwater were to reach Belle Chasse, at least 20,000 more people would need potable water. The bed of the Mississippi River is below sea level throughout the entire length of Louisiana, so when drought reduces the flow of the river, the salty, denser ocean water can creep further upstream. WWNO 89.9 (New Orleans, La.), Sept 19, 2023 Plaquemines Parish has been dealing with water line breaks and the saltwater wedge in the Mississippi River for months as drought affects the region. Lower parts of Plaquemines Parish have not had clean drinking water for months due to a saltwater wedge creeping up the Mississippi River. The U.S. Army Corps of Engineers built an underwater sill in July to slow the movement of the wedge upstream, but the wedge is expected to push past the sill and reach Belle Chasse by October 3. WWL-TV (New Orleans, La.), Sept 17, 2023

5-Day Uncertainty Track last updated Fri, 20 Oct 2023 02:48:02 GMT


Wind Speed Probabilities last updated Fri, 20 Oct 2023 03:24:11 GMT

Issued at 1100 PM AST Thu Oct 19 2023 000 WTNT45 KNHC 200246 TCDAT5 Tropical Storm Tammy Discussion Number 7 NWS National Hurricane Center Miami FL AL202023 1100 PM AST Thu Oct 19 2023 Tammy appears to be in the process of reorganizing. The low-level circulation we had been following appears to have slowed down tonight, as confirmed by the last few fixes from the NOAA-P3 reconnaissance aircraft that has been in the storm tonight. In addition, the Tail-Doppler Radar (TDR) on board the aircraft has shown that the tilt between the low-level (1 km) and mid-level (5 km) center has been reduced as a result of this slowdown. There is also evidence of convection beginning to wrap into the up-shear quadrant of the system on both GPM microwave imagery available at 2350 UTC and recent radar images from Barbados. However, this restructuring has not yet resulted in an increase in the maximum sustained winds, which remain about 50 kt for this advisory, in agreement with a blend of the subjective Dvorak data and the earlier TDR data in the northeast quadrant. Recon fixes indicate the Tammy is still moving generally west-northwestward but slower at 290/9 kt. There is not much new to report from the track reasoning this cycle. An enhanced mid-level ridge (anomalously strong for this time of year) is beginning to shift eastward as a sharp mid-latitude trough approaches from the west. This shift should allow Tammy to turn gradually to the northwest and then north-northwest over the next 2-3 days. However, the forward motion related to this turn is forecast to be rather slow, related to an upper-level cutoff low south of the mid-level ridge weakening its steering influence on Tammy. Compared to 24 hours ago, the global model guidance is in better agreement on this track solution, but continues to trend slower and a bit east of the prior cycle. Thus, the NHC track forecast has been adjusted quite a bit slower and a little further east of the prior one, blending the prior track with the consensus aids HCCA and TVCN. It should be noted that both the GFS and ECMWF remain on the east side of the guidance envelope, and further adjustments in that direction may be needed in subsequent cycles. Tammy is still forecast to recurve to the north-northeast by the end of the forecast period. However, there is a substantial amount of spread in the along-track direction in both the GFS and ECMWF ensembles, related to whether or not Tammy is fully picked up by the mid-latitude trough. Assuming Tammy is in the process of becoming better vertically aligned, the storm has an opportunity to intensify as shear remains light to moderate (10-20 kt) and sea-surface temperatures remain quite warm (near 30 C). The guidance this cycle shows a bit more short-term intensification than before, and the NHC intensity forecast follows suit, showing gradual intensification to hurricane intensity in 36 h and a bit more intensification through day 4. Increasing southwesterly vertical wind shear at the end of the of forecast period may begin to induce weakening as Tammy moves into the stronger mid-latitude flow ahead of the mid-latitude trough. The NHC intensity forecast is close to or just a shade under the latest consensus aids HCCA and IVCN. KEY MESSAGES: 1. Tropical storm conditions are expected to begin in portions of the Lesser Antilles beginning Friday, where a tropical storm warning is in effect. Tropical storm and hurricane conditions are possible elsewhere in the Leeward Islands where hurricane and tropical storm watches are currently in effect. Additional watches and warnings could be required on Friday. 2. Heavy rains from Tammy will begin to affect the Leeward and northern Windward Islands on Friday, spreading into the British and U.S. Virgin Islands and Puerto Rico over the weekend. This rainfall may produce isolated flash and urban flooding, along with isolated mudslides in areas of higher terrain. FORECAST POSITIONS AND MAX WINDS INIT 20/0300Z 13.8N 57.1W 50 KT 60 MPH 12H 20/1200Z 14.3N 58.2W 55 KT 65 MPH 24H 21/0000Z 15.3N 59.9W 60 KT 70 MPH 36H 21/1200Z 16.6N 61.3W 65 KT 75 MPH 48H 22/0000Z 18.0N 62.0W 70 KT 80 MPH 60H 22/1200Z 19.7N 62.5W 75 KT 85 MPH 72H 23/0000Z 21.5N 63.0W 80 KT 90 MPH 96H 24/0000Z 24.0N 62.0W 80 KT 90 MPH 120H 25/0000Z 28.0N 57.5W 75 KT 85 MPH $$ Forecaster Papin

...TAMMY SLOWING DOWN AND REORGANIZING... ...TROPICAL STORM CONDITIONS AND HEAVY RAIN EXPECTED TO BEGIN TOMORROW FOR PORTIONS OF THE LEEWARD ISLANDS... As of 11:00 PM AST Thu Oct 19 the center of Tammy was located near 13.8, -57.1 with movement WNW at 10 mph. The minimum central pressure was 1001 mb with maximum sustained winds of about 60 mph.

Issued at 0300 UTC FRI OCT 20 2023 000 FONT15 KNHC 200243 PWSAT5 TROPICAL STORM TAMMY WIND SPEED PROBABILITIES NUMBER 7 NWS NATIONAL HURRICANE CENTER MIAMI FL AL202023 0300 UTC FRI OCT 20 2023 AT 0300Z THE CENTER OF TROPICAL STORM TAMMY WAS LOCATED NEAR LATITUDE 13.8 NORTH...LONGITUDE 57.1 WEST WITH MAXIMUM SUSTAINED WINDS NEAR 50 KTS...60 MPH...95 KM/H. Z INDICATES COORDINATED UNIVERSAL TIME (GREENWICH) ATLANTIC STANDARD TIME (AST)...SUBTRACT 4 HOURS FROM Z TIME EASTERN DAYLIGHT TIME (EDT)...SUBTRACT 4 HOURS FROM Z TIME CENTRAL DAYLIGHT TIME (CDT)...SUBTRACT 5 HOURS FROM Z TIME WIND SPEED PROBABILITY TABLE FOR SPECIFIC LOCATIONS CHANCES OF SUSTAINED (1-MINUTE AVERAGE) WIND SPEEDS OF AT LEAST ...34 KT (39 MPH... 63 KM/H)... ...50 KT (58 MPH... 93 KM/H)... ...64 KT (74 MPH...119 KM/H)... FOR LOCATIONS AND TIME PERIODS DURING THE NEXT 5 DAYS PROBABILITIES FOR LOCATIONS ARE GIVEN AS OP(CP) WHERE OP IS THE PROBABILITY OF THE EVENT BEGINNING DURING AN INDIVIDUAL TIME PERIOD (ONSET PROBABILITY) (CP) IS THE PROBABILITY OF THE EVENT OCCURRING BETWEEN 00Z FRI AND THE FORECAST HOUR (CUMULATIVE PROBABILITY) PROBABILITIES ARE GIVEN IN PERCENT X INDICATES PROBABILITIES LESS THAN 1 PERCENT PROBABILITIES FOR 34 KT AND 50 KT ARE SHOWN AT A GIVEN LOCATION WHEN THE 5-DAY CUMULATIVE PROBABILITY IS AT LEAST 3 PERCENT. PROBABILITIES FOR 34...50...64 KT SHOWN WHEN THE 5-DAY 64-KT CUMULATIVE PROBABILITY IS AT LEAST 1 PERCENT. - - - - WIND SPEED PROBABILITIES FOR SELECTED LOCATIONS - - - - FROM FROM FROM FROM FROM FROM FROM TIME 00Z FRI 12Z FRI 00Z SAT 12Z SAT 00Z SUN 00Z MON 00Z TUE PERIODS TO TO TO TO TO TO TO 12Z FRI 00Z SAT 12Z SAT 00Z SUN 00Z MON 00Z TUE 00Z WED FORECAST HOUR (12) (24) (36) (48) (72) (96) (120) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - LOCATION KT PONCE PR 34 X X( X) 1( 1) 2( 3) 4( 7) 2( 9) X( 9) AGUADILLA PR 34 X X( X) X( X) 2( 2) 3( 5) 2( 7) X( 7) SAN JUAN PR 34 X X( X) X( X) 1( 1) 4( 5) 1( 6) X( 6) VIEQUES PR 34 X X( X) 3( 3) 3( 6) 8(14) 3(17) X(17) SAINT THOMAS 34 X X( X) 4( 4) 6(10) 11(21) 3(24) X(24) SAINT THOMAS 50 X X( X) X( X) 1( 1) 4( 5) 1( 6) X( 6) SAINT THOMAS 64 X X( X) X( X) X( X) 1( 1) 1( 2) X( 2) SAINT JOHN 34 X X( X) 5( 5) 7(12) 11(23) 3(26) X(26) SAINT JOHN 50 X X( X) X( X) 1( 1) 5( 6) 1( 7) X( 7) SAINT JOHN 64 X X( X) X( X) X( X) 1( 1) 1( 2) X( 2) SAINT CROIX 34 X X( X) 5( 5) 6(11) 7(18) 3(21) X(21) SAINT CROIX 50 X X( X) X( X) 1( 1) 2( 3) 1( 4) X( 4) SAINT MAARTEN 34 X 3( 3) 14(17) 30(47) 12(59) 1(60) X(60) SAINT MAARTEN 50 X X( X) 2( 2) 17(19) 12(31) X(31) X(31) SAINT MAARTEN 64 X X( X) X( X) 5( 5) 7(12) 1(13) X(13) SABA 34 X 3( 3) 15(18) 23(41) 8(49) 2(51) X(51) SABA 50 X X( X) 2( 2) 13(15) 7(22) X(22) X(22) SABA 64 X X( X) X( X) 4( 4) 4( 8) X( 8) X( 8) ST EUSTATIUS 34 X 4( 4) 19(23) 25(48) 7(55) 1(56) X(56) ST EUSTATIUS 50 X X( X) 3( 3) 18(21) 5(26) 1(27) X(27) ST EUSTATIUS 64 X X( X) X( X) 6( 6) 4(10) X(10) X(10) ST KITTS-NEVIS 34 X 5( 5) 26(31) 25(56) 5(61) 1(62) X(62) ST KITTS-NEVIS 50 X X( X) 7( 7) 20(27) 4(31) 1(32) X(32) ST KITTS-NEVIS 64 X X( X) 1( 1) 7( 8) 3(11) X(11) X(11) BARBUDA 34 1 5( 6) 44(50) 28(78) 5(83) X(83) X(83) BARBUDA 50 X X( X) 16(16) 29(45) 6(51) X(51) X(51) BARBUDA 64 X X( X) 3( 3) 13(16) 3(19) X(19) X(19) ANTIGUA 34 X 3( 3) 45(48) 18(66) 3(69) X(69) X(69) ANTIGUA 50 X X( X) 10(10) 13(23) 2(25) X(25) X(25) ANTIGUA 64 X X( X) 1( 1) 2( 3) X( 3) X( 3) X( 3) GUADELOUPE 34 1 16(17) 49(66) 7(73) 2(75) X(75) X(75) GUADELOUPE 50 X 2( 2) 36(38) 7(45) 1(46) X(46) X(46) GUADELOUPE 64 X X( X) 9( 9) 5(14) X(14) X(14) X(14) AVES 34 X 3( 3) 5( 8) 5(13) 3(16) X(16) X(16) DOMINICA 34 1 18(19) 26(45) 3(48) 1(49) X(49) X(49) DOMINICA 50 X 2( 2) 12(14) 2(16) X(16) X(16) X(16) DOMINICA 64 X X( X) 2( 2) 1( 3) X( 3) X( 3) X( 3) MARTINIQUE 34 X 9( 9) 8(17) 1(18) 1(19) X(19) X(19) SAINT LUCIA 34 1 4( 5) 5(10) 2(12) 1(13) X(13) X(13) SAINT VINCENT 34 1 1( 2) 4( 6) 1( 7) 1( 8) X( 8) X( 8) BARBADOS 34 2 5( 7) 3(10) 1(11) X(11) X(11) X(11) GRENADA 34 X 2( 2) 1( 3) 1( 4) X( 4) X( 4) X( 4) $$ FORECASTER PAPIN