June 2017: Typical Summertime WX To End Month

[cperk]

srainhoutx i was starting to buy into the euro forecast,but the ukmet has my attention.

[srainhoutx]

Saturday morning briefing from Jeff:

Disturbance over the western Caribbean and strong tropical wave (92L) over the central Atlantic now have a high (70%) chance of development over the next 5 days.

Tropical system continues to be likely in the Gulf of Mexico next week.

Gulf of Mexico:

Surface observations and satellite images indicate that showers and thunderstorms continue to gradually increase across the western Caribbean Sea and that surface pressures are starting to fall. The falling surface pressures indicates that the expected broad area of low pressure is starting to develop as forecast models have been suggesting. Based on satellite images it appears the lowering pressures is very large and likely still an opened trough axis.

Global models continue to be consistent on slowly developing a large low pressure system across the western Caribbean Sea and the southern Gulf of Mexico, but have become as consistently split on what happens with this system over the Gulf. One group of models develops the system faster and is stronger taking it quickly northward out of the western Caribbean Sea and into the western FL panhandle as a strong tropical storm, while another group of models brings a much weaker system WNW/NW into the western Gulf of Mexico with a very large area of tropical storm force winds and heavy rainfall north and east a broad surface center. Given the satellite images this morning without any sustained deep convection over any well defined center and the overall very large nature of the system gives some support to the weaker westward solution. The eastern camp of models show a stronger system evolving out of a possible vorticity center that would be rotating around the average larger circulation. While this is possible, in situations such as this, it is usually a better course to follow the larger mean center circulation which can at times have numerous vorticity centers rotating around it.

Upper air conditions are forecasted to gradually become more favorable for development as wind shear relaxes across the NW Caribbean Sea. Water vapor images show as slight digging trough axis over the southern US currently and this trough is expected to linger into the middle of next week which may help to impart some shear across the Gulf. In fact this may be one reason why the ECWMF is keeping the system weaker and all the weather to the right of the center. This would suggest the possibility of some degree of W/WSW shear across the system.

Uncertainty remains high especially on when and where a broad center may finally form and where the system may track. Will favor the weaker and western solution at this time in agreement with coordinated NHC/WPC points.

For now will make no changes to any of the forecasted seas, winds, tides, or rainfall chances until more certainty emerges. Already expecting 3-4 foot seas by Tuesday/Wednesday which will likely start to push tides up into the 1.0-1.5 foot range. Mid to late week could be very wet or bone dry depending on how much ridging aloft is maintained over the region.

Note: USAF mission is planned for Monday over the Gulf of Mexico to investigate this system

92L:

Strong tropical wave 1600 miles east of the Windward Islands is moving westward at 15-20mph and continues to show signs of organization. Conditions appear favorable for some development of this system as it nears the southern Windward Islands next week. While it would be very rare for a tropical system to form this far east this early in the season it does appear that this wave may develop. This system is embedded within the easterly flow on the south side of a sprawling sub-tropical ridge across the central Atlantic which will continue a westward motion between 15-20mph for the next several days. The track forecast is of high confidence as noted by the tight clustering of the track guidance. The intensity guidance is in poor agreement from showing no development at all to a near hurricane. Think development into a least a weak tropical storm is the most likely solution at this time prior to arrival into the southern Windward Islands. Conditions over the eastern Caribbean Sea appear hostile with strong upper level shear in place next week which will likely result in the system weakening however some of the latest ensemble members do keep the system alive into the central Caribbean Sea now…so that is something to watch.

[srainhoutx]

Tasking for Reconnaissance Missions to the NW Caribbean and Gulf have just been Updated. The first RECON will be tomorrow afternoon...

Code: Select all

WEATHER RECONNAISSANCE FLIGHTS
CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.
1230 PM EDT SAT 17 JUNE 2017
SUBJECT: TROPICAL CYCLONE PLAN OF THE DAY (TCPOD)
         VALID 18/1100Z TO 19/1100Z JUNE 2017
         TCPOD NUMBER.....17-017

I.  ATLANTIC REQUIREMENTS
    1. SUSPECT AREA (NW CARIBBEAN)
       FLIGHT ONE -- TEAL 71          FLIGHT TWO -- TEAL 72
       A. 18/2000Z                    A. 19/1130Z,1730Z
       B. AFXXX 01AAA INVEST          B. AFXXX 0202A CYCLONE
       C. 18/1730Z                    C. 19/0945Z
       D. 20.0N 86.5W                 D. 22.0N 87.5W
       E. 18/1930Z TO 18/2330Z        E. 19/1100Z TO 19/1730Z
       F. SFC TO 10,000 FT            F. SFC TO 10,000 FT

    2. OUTLOOK FOR SUCCEEDING DAY:
       A. CONTINUE 6-HRLY FIXES IF ABOVE SYSTEM DEVELOPS AND REMAINS
          A THREAT.
       B. POSSIBLE LOW-LEVEL INVEST MISSION OVER CENTRAL ATLANTIC EAST
          OF TRINIDAD NEAR 9.5N 58.0W FOR 19/1800Z.

[srainhoutx]

Updated Weather Prediction Center Extended Range Discussion with the Bolded and Underlined Commentary regarding the likely Gulf System...

EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1200 PM EDT SAT JUN 17 2017

VALID 12Z TUE JUN 20 2017 - 12Z SAT JUN 24 2017

...RECORD HEAT OVER CALIFORNIA AND THE DESSERT SOUTHWEST THIS
WEEKEND WILL CONTINUE INTO THE MIDDLE OF NEXT WEEK...

...A DISTURBANCE CURRENTLY BEING MONITORED BY THE NATIONAL
HURRICANE CENTER COULD BRING HEAVY RAINFALL TO THE GULF COAST NEXT
WEEK, BUT THE FORECAST REMAINS EXTREMELY UNCERTAIN...


...PATTERN OVERVIEW/MODEL EVALUATION...

AN EXPANSIVE UPPER RIDGE WILL REMAINED ANCHORED OVER CALIFORNIA
AND THE DESSERT SOUTHWEST THROUGH THE MIDDLE OF NEXT WEEK. FLOW
SHOULD BE FAST AND ZONAL NORTH OF THE STRONG RIDGE FROM THE
PACIFIC NORTHWEST TO THE NORTHERN ROCKIES, WHILE A DOWNSTREAM
BROAD UPPER TROUGH WILL IMPACT THE EASTERN HALF OF THE NATION
EARLY TO MID NEXT WEEK. CONFIDENCE IN THE LARGE SCALE FLOW OVER
THE U.S. BEGINS TO BREAK DOWN BY THE END OF NEXT WEEK, ESPECIALLY
OVER THE NORTHWESTERN U.S. WHERE DETERMINISTIC GUIDANCE IS SHOWING
A WIDE RANGE OF SOLUTIONS WITH THE EVOLUTION OF AN UPPER LOW
POTENTIALLY DROPPING SOUTHWARD OUT OF THE GULF OF ALASKA LATE NEXT
WEEK. MODELS ARE ALSO SHOWING A WIDE RANGE OF SOLUTIONS EARLIER
IN THE FORECAST PERIOD WITH THE DEVELOPMENT OF A POTENTIAL
TROPICAL SYSTEM IN THE GULF OF MEXICO EARLY NEXT WEEK. THE CMC,
GFS, AND EVEN THE LATEST 06Z GEFS MEAN TRACK A SYSTEM TOWARDS THE
CENTRAL GULF COAST/FLORIDA PANHANDLE ON TUESDAY, WHILE THE UKMET,
ECMWF, AND ECMWF ENSEMBLE MEAN BRING A SYSTEM WESTWARD TOWARDS
EASTERN MEXICO/SOUTH TEXAS. THE GEFS AND ECMWF INDIVIDUAL
ENSEMBLE MEMBERS EACH CLUSTERED AROUND THEIR DETERMINISTIC RUNS,
SUGGESTING BOTH THE GFS AND ECMWF ARE WITHIN THE RANGE OF POSSIBLE
SOLUTIONS.

THE WPC MEDIUM RANGE FORECAST STARTED WITH A BLEND BETWEEN
DETERMINISTIC AND ENSEMBLE MEAN GUIDANCE, BUT THEN RELIED MORE
HEAVILY ON THE GEFS/ECMWF ENSEMBLE MEANS BY DAY 6-7
(FRIDAY-SATURDAY) IN ORDER TO ACCOUNT FOR THE UNCERTAINTY WITH
FLOW OVER THE NORTHWESTERN U.S. LATE NEXT WEEK. ALSO, THE
FORECAST WAS MANUALLY ADJUSTED TOWARDS THE ECWMF/ECWMF ENSEMBLE
MEAN SOLUTION OVER THE GULF OF MEXICO EARLY IN THE FORECAST PERIOD
SINCE IT MATCHED BETTER WITH CONTINUITY. HOWEVER, ADDITIONAL
MODIFICATIONS MAY BE NEEDED AFTER THE 17Z WPC/NHC TROPICAL
COORDINATION CALL.


...WEATHER HIGHLIGHTS...

CONSECUTIVE DAYS OF RECORD BREAKING HEAT ARE EXPECTED BENEATH THE
STRONG UPPER RIDGE PARKED OVER CALIFORNIA AND THE DESSERT
SOUTHWEST THROUGH THE MIDDLE OF NEXT WEEK, WITH DAYTIME
TEMPERATURES POSSIBLY EXCEEDING THE 120 DEGREE MARK IN SOME
LOCATIONS. HEAVY RAINFALL COULD THREATEN THE GULF COAST STATES,
BUT THE TIMING, LOCATION, AND MAGNITUDE OF THE EVENT STILL HINGES
ON THE VERY UNCERTAIN FORECAST OF A DISTURBANCE LIFTING OUT OF THE
YUCATAN (PLEASE REFER TO THE NATIONAL HURRICANE CENTER FOR THE
LATEST INFORMATION). TO THE NORTH...DAILY ROUNDS OF CONVECTION
WITH PERHAPS SOME NOCTURNAL MESOSCALE COMPLEXES WILL BE POSSIBLE
OVER THE UPPER MIDWEST...MIDDLE MISSISSIPPI VALLEY...AND OHIO
VALLEY.


GERHARDT

[srainhoutx]

INVEST 93L has been designated for the NW Caribbean/Gulf of Mexico Tropical Disturbance.

[cisa]

What are the early gut feelings that you guys are having. Understanding there's a lot of uncertainly, some of you, I'be been talking with since Rita, and your early gut feelings are good starting point for me. Happy Father's Day all.
Hi srain

[srainhoutx]

Saturday afternoon Update from Jeff:

NHC has raised the chances for tropical cyclone development to 80% and designated the area of low pressure in the western Caribbean Sea as 93L.

Surface observations and high resolution GOES 16 images show a surface low has formed over the Gulf of Honduras with surface pressures having fallen from 1012mb yesterday to around 1009mb this morning. Deep convection has developed to the north and east of this broad surface reflection and the surface low is moving NNW around 5-10mph. Since the National Hurricane Center has now tagged a surface circulation model guidance is being run on the system with a fixed 1009mb center. This might help reduce the very large guidance spread in track solutions across the Gulf of Mexico. Looking at some of the early runs coming in of the ensemble members might suggest the western track solution is preferred.

Note: USAF mission planned for Monday is now being scheduled to launch on Sunday and into the western Caribbean Sea to determine if a tropical depression has formed. Expect additional multiple missions into the Gulf of Mexico next week as the system lifts NW into the SC Gulf of Mexico.

Also NHC has tasked a possible USAF mission into the Atlantic wave east of Windward Islands for Monday if needed

Residents along the US Gulf coast should closely monitor the progress of this system as it appears likely that a tropical storm will be in the Gulf of Mexico next week.

[srainhoutx]

The 12Z ECMWF suggest 93L will develop and head toward the NE Mexico/S Texas Border bringing copious rainfall across the entire Texas Coast.

[srainhoutx]

The afternoon Updated Weather Prediction Center Day 3 through 7 Surface Charts are now available. Looks like the WPC/NHC Coordination call has brought some changes that may have some potential rainfall and higher tidal impacts across Coastal Texas into Louisiana.

[srainhoutx]

Also the 7 Day Quantitative Precipitation Forecast just updated. Use these graphics with extreme caution as they are subject to change in this complex and complicated forecasting scenario.

[Cromagnum]

That latest map looks like Texas is going to stay high and dry for the most part.

[Scott747]

That latest map looks like Texas is going to stay high and dry for the most part.

Not so fast...

[ticka1]

That latest map looks like Texas is going to stay high and dry for the most part.

what map and the llc hasnt developed and its not in GOM yet

[DoctorMu]

Split decision still. The gap between the Western ridge and Bermuda high is the key.




Gyre she blows!

[Andrew]

GFS and GFS Parallel show a Florida hit still while the CMC shifts westward to Louisiana. The ECMWF shows a central Texas hit and finally the UKMET has a south/central Texas hit.

[srainhoutx]

Forecaster Jack Beven increases chances to a 9 out of 10 or 90% for Tropical Cyclone or Subtropical Cyclone Development.

As of 8:00 am EDT Sun Jun 18 2017 ...
A broad area of low pressure located over the northwestern Caribbean
Sea continues to produce a large area of disorganized showers and
thunderstorms. Gradual development of this system is expected while
it moves slowly northwestward across the Yucatan Peninsula later
today and over the southern or central Gulf of Mexico on Monday and
Tuesday, where a tropical or subtropical cyclone is likely to form.
Regardless of development, heavy rains are expected over portions of
Central America, the Yucatan Peninsula, Jamaica, the Cayman Islands,
and western Cuba during the next several days. An Air Force Reserve
Hurricane Hunter aircraft is scheduled to investigate this system
later today, if necessary.
* Formation chance through 48 hours...medium...60 percent.
* Formation chance through 5 days...high...90 percent.

[TexasBreeze]

I could see the eastern solution playing out, because the system is lopsided east and could follow the convective blowups tugging it east instead of west to Mexico or south TX. We have northerly flow here which would shear it too. Maybe LA to FL panhandle in play??? IMO though.

[srainhoutx]

NWS/NHC Surface Chart for 72 Hours suggests NE Mexico/S Texas solution is likely. This was issued at 07Z after the ECMWF/UKMet guidance came out for 00Z.

[srainhoutx]

Michael Ventrice‏Verified account @MJVentrice · 56m56 minutes ago
Latest Calibrated ECMWF EPS 80-90% with western MDR system. Gulf of Mexico system bearish compared to NHC - 60% though tracks into Texas

[srainhoutx]

From Phillipe Papin of Albany who has done extensive research on Monsoonal Gyres regarding the ECMWF solution from 00Z. Phillipe is the "go to" Specialist with his research in this sort of situation.