# Presentation: 239041

## Tropical Analysis and Forecast Branch (TAFB) Overview and Challenges

**Tropical Analysis and Forecast Branch (TAFB) Overview and Challenges**
***                                         ***

-    Eric Blake
- 3-17-04

**Notes:**
Happy St. Patrick’s Day... I am going to talk about what TAFB does in a broad spectrum and the types of challenges we have in the Atlc basin.

## TPC/WFO MFL  OCT 4 , 2000

**Florida Turnpike**

**Florida Int’l University**

**Notes:**
We moved here in 1995 to escape the wind threat from being right along the coast e of US1 over in Coral Gables.  However as you can see, we are still vulnerable to a flooding threat, this is after precursor of t.s. leslie moved across the state.. Major flooding!

## OUTLINE 

**Brief TAFB duties and products overview**
**Data and Model Sources**
**Forecast Challenges**
**Possible TC graphic and verification **
**Future**

## Hurricane Specialists Unit 
Tropical Analysis and Forecast Branch (TAFB)  
Technical Support Branch (TSB) 
Storm Surge Unit
Chief Aerial Reconnaissance      Coordination All Hurricanes (CARCAH)

**Hurricane Specialists Unit **
**Tropical Analysis and Forecast Branch (TAFB)  **
**Technical Support Branch (TSB) **
**Storm Surge Unit**
**Chief Aerial Reconnaissance      Coordination All Hurricanes (CARCAH)**

**Notes:**
4 main branches– hur specialists do most of the tc related products, we do most of the marine products, tsb is a major contributor with the computing effort, the storm surge unit 
Is in play during landfalls and of course CARCAH is responsible for recon in the atlc, e pac and near hawaii.

## Slide 6

**Notes:**
Tafb is the largest group, with about 17 shift workers working 24/7.  

## Tropical Analysis and 

- TAFB provides operational tropical cyclone support during the tropical seasons through manpower, forecast and media support, radar tracking, and tropical cyclone position and intensity estimates based on the Dvorak technique.

- _T_ropical _A_nalysis and
- _F_orecast _B_ranch (TAFB)

## TAFB Duties

**Issue marine forecasts (text and graphical) for the tropical and sub-tropical Atlantic and Northeast and Southeast Pacific Oceans.**
**Produce 3-hourly tropical surface analysis**
**Tropical Weather Discussions**
**Estimate intensity and position of tropical cyclones using the Dvorak technique**

**Notes:**
NAVTEX, High Seas, Offshore, Gulf of Mexico
Surface analysis from 20E over Africa to 160w w of hawaii.
Twd for the atlc and epac
In the season we use the dvorak technique to classfy tcs

## TAFB Duties 

** ****Provide Satellite Rainfall Estimates                                                                                        **
** ****WSR-88D radar fixes for land-falling ****	****	****	****tropical cyclones**
** ****Media support during tropical cyclone ****	****	****events****   **
** ****Tropical cyclone forecast support**
** ****FEMA -Hurricane Liaison Team (HLT)**

- TAFB Duties

**Notes:**
Satellite rainfall for caribbean events, slow-moving tropical waves
Work the radar during landfalls... position estimate, also analyze doppler data
Massive phone support, HLT, epac advisories

## TAFB Production Suite 

**Atlantic Desk**
**Marine Weather Discussion (2)**
**High Seas - HSFAT2 (4) **
**Offshore Waters **
**OFFNT3 (4) **
**OFFNT4 (4) **
**Seastate Analysis (4)**
**ATLC Wind/Wave Charts  (8)**** **
**Analyst/Forecaster**
**Tropical SFC Analysis (8)**
**TWDAT (4) **
**Wave Period/Swell (6)**
**PANAM Temps (2)**

**Pacific Desk **
**Dvorak Classifications  **
**(4 Synoptic/Intermediate)**
**TWDEP (4) **
**High Seas**
**HSFEP2 (4)**
**HSFEP3 (4)**
**High Wind/Danger Area **
**Atlantic**
**Pacific  **
**EPAC Wind/Wave Charts (11) **

**Notes:**
About 100 products a day

## TAFB High Seas Forecast Areas

## Offshore Forecast Area

## Atlantic Surface Analysis

**Notes:**
Surface analysis has tropical waves, significant deep convection, 24 hour high/low forecasts

## Atlantic Wind/Wave Forecast

## Atlantic Tropical Cyclone Hazard Area Graphic

**1 June - 30 Nov**** **

**Notes:**
Produced during hurricane season, this is the average error of our forecasts spread out in time

## High Wind Area Graphic

**High Wind Area Graphic**

**Notes:**
In the offseason we produce a high wind graphic, showing 25 kt or greater in our area and gales or greater n of 31n

## What’s new in 2004

** **
** ****3 hourly surface analyses over tropical  N. American region.**

- Products

**Notes:**
12 planet thru awips
Late december we started the 3 hourly analysis, taking over from hpc over the w atlc, nw carib, gulf, mexico and epac.

## Sparse data - need for remote sensed data
Reliable guidance over the tropics (or lack thereof)
Local effects (sea-breeze, topography, diurnal)
Small amplitude/scale associated with many significant weather features
Reliability of ship observations (not quite as good as land stations)

- Reliable guidance over the tropics (or lack thereof)
- Local effects (sea-breeze, topography, diurnal)
- Small amplitude/scale associated with many significant weather features
- Reliability of ship observations (not quite as good as land stations)

- Challenges of analyzing and
-  forecasting tropical weather

## Typical 24 hour Composite of Atlantic Ship and Buoy Observations

## Numerical Guidance (GFS,ETA,NWW3,UKMET,NOGAPS, GFDL/GFDN, CMC, Ensemble probabilities)
Surface Observations (metar, ship, buoys)
Satellite 
Radar  including Caribbean countries
Upper Air Observations
Weather reconnaissance data

- Surface Observations (metar, ship, buoys)
- Satellite
- Radar  including Caribbean countries
- Upper Air Observations
- Weather reconnaissance data

- Conventional Data

- Ensemble Probabilities

- Spaghetti Diagram

## Conventional Data Often is Not Enough

- TAFB relies on additional sources of data such as microwave and remote-sensing data in order to gain a better understanding of the current/forecast situation, especially in data sparse regions

## Satellite Derived Winds

- Quikscat

- Additional Data used by TAFB

## Quikscat

## Quikscat

## Satellite Derived Winds
Quikscat

- Quikscat

- SSMI

- Additional Data used by TAFB

## SSMI

## Satellite Derived Winds
Quikscat
SSMI

- Quikscat
- SSMI

- ERS-2 Data

- Additional Data used by TAFB

## Slide 30

## Forecast Challenges

**Wind “funnelling” through passages**
**NWW3 biases**
**Central Caribbean Sea strong trades**

**YUCATAN **
** ****CHANNEL**

**  ****FLORIDA  STRAITS**

**BAHAMA **
**  ****BANK**

**WINDWARD **
**  ****PASSAGE**

**    ****MONA **
**  ****PASSAGE**

**    ****ANEGADA **
**     ****PASSAGE**

**  ****GULF OF **
**HONDURAS**

## Gulf of Mexico Examples

**Recent examples of NWW3 under-forecasts along frontal boundary in the Gulf of Mexico and Western Atlantic.**
**Next few slides show examples of ship and buoy observations (red) with the NWW3, significant wave height forecasts (black) valid at the time of the observations.**
**Most observations in Gulf of Mexico and extreme Western Atlantic are moored buoys and are considered extremely reliable.**

## NWWIII under-forecasting seas behind front in NW Gulf of Mexico6 h forecast

- NWWIII under-forecasting seas behind front in NW Gulf of Mexico6 h forecast

## Similar example:9 h forecast

## Example of an over-forecast of seas in central Gulf of Mexico well behind the front.24 h forecast

## NOAA Wavewatch III Biases

- Does not develop seas fast enough behind strong cold fronts, particularly in the Gulf of Mexico and W Atlantic, and is often slow in subsiding the seas beyond 24 hours after frontal passage.
- This bias likely due to improper handing of initial growth of seas, as well as under-forecasting of winds by AVN model.
- Under-forecast of seas in Caribbean during strong trade wind events (also largely due to under-forecasting of winds.
- Occasionally over-forecasts swell heights in TAFB forecast areas.

##       GFS 10-m wind forecast depicting

**      ****GFS 10-m wind forecast depicting**
**funneling winds in the Yucatan Channel**** **

## 1135 UTC 29 November 2003 QUIKSCAT PASS 

**1135 UTC 29 November 2003 QUIKSCAT PASS **
**    ****depicting higher winds in Yucatan Channel **

## 2319 UTC 11 November 2003 QUIKSCAT PASS 

**2319 UTC 11 November 2003 QUIKSCAT PASS **
**    ****depicting higher winds in Florida Straits  **

##     NWW3 wave height forecast depicting 

**    ****NWW3 wave height forecast depicting **
**       ****lower seas in the Bahama Bank **** **

## GOMEX Shelf Water Event25 January 2004 confirmed by Quikscat

- This event was similar to the southerly Gulf Stream events off the mid-Atlantic and New England waters.  The mid-Atlantic and New England events were documented by OPC and are characterized by warm southerly winds which do not mix down to the surface over the cool waters west of the Gulf Stream.

## Between about 0000 and 1200 UTC 25 January strong southerly winds occurred over portions of the western Gulf of Mexico.
Offshore buoy over the warmer Gulf waters reported 28 to 33 kt sustained winds with gusts to 39 kt while winds over the cooler shelf waters were around 15 kt with gusts to 20 kt. 
Quikscat from 0050 UTC detected the weaker winds near shore.  The gradient of weaker winds matched well with SST data from buoys and satellite.

- Offshore buoy over the warmer Gulf waters reported 28 to 33 kt sustained winds with gusts to 39 kt while winds over the cooler shelf waters were around 15 kt with gusts to 20 kt.
- Quikscat from 0050 UTC detected the weaker winds near shore.  The gradient of weaker winds matched well with SST data from buoys and satellite.

## Warm “Tongue”

**Warm “Tongue**”

**Cold Shelf  Waters**

## Slide 45

## Quikscat from 0050 UTC 25 January.  Surface observations from 0400 UTC

- SSTs in Red

## Coordination

**Crucial part of operations due to overlap of OFF and CWF areas because of NAVTEX products**.
**Means of Coordination**
**Hurricane Hotline - Large Synoptic scale systems affecting multiple offices**
**Telephone call to individual offices**
**Marine Weather Discussion**
**TAFB also coordinates with OPC and WFO Honolulu/CPHC.**

## Hurricane Isabel Coordination

**EAST CENTRAL FLORIDA FORECAST DISCUSSION**
**NATIONAL WEATHER SERVICE MELBOURNE FL**
**3:30 AM EDT SAT SEP 13 2003**
**	****MARINE... ****COORDINATION CALL FROM TAFB**** INDICATED THAT INCREASING SWELL HEIGHTS FROM ISABEL COULD BE ARRIVING IN OUR OFFFSHORE WATERS... BEYOND 60 MILES OF SHORE... AS EARLY AS SUNDAY NIGHT OR MONDAY MORNING.  HAVE MADE TIMING AND WAVE HEIGHTS ADJUSTMENTS TO THE COASTAL WATERS FORECAST.  WILL MOST LIKELY NEED TO POST SMALL CRAFT EXERCISE CAUTION SUNDAY AND SMALL CRAFT ADVISORIES FOR SEAS BY MONDAY.**
**AREA FORECAST DISCUSSION**
**NATIONAL WEATHER SERVICE JACKSONVILLE FL**
**3:20 AM EDT SAT SEP 13 2003**
**	****MARINE...OBS INDICATING LONG PERIOD SWELLS ATTRIBUTED TO HURRICANE ISABEL WITH PERIODICITY ~ 14 SECONDS.  WILL KEEP SEAS 3 TO 5 FEET THROUGH SUNDAY.  OFFSHORE WATERS WILL LIKELY REACH SCEC CONDITIONS BY SUNDAY NIGHT DUE TO COMBINED SEAS...FOLLOWED BY SCA CONDITIONS ON MONDAY.  THANKS FOR THE ****COORDINATION CALL TAFB****.**

## Introduction of the term“Possible” Tropical Cyclone

**TAFB realized a better service could be provided to mariners by giving a “heads-up” to “possible” TC development.**
**TAFB began experimenting with using the term “Possible” Tropical Cyclone in some graphic and text products during the 2001 tropical season.**

## “Possible” Tropical Cyclone Forecasts

**TAFB forecasters and duty hurricane specialist (HS) collaborate on areas of possible TC development  **
**HS and TAFB forecasters use satellite analysis (Dvorak) to determine the current strength and structure of a system**
**Use numerical models to determine its likelihood of future development**

## “Possible” Tropical Cyclone Forecasts

**If it is determined that TC development is “possible” within 36 hours,  the HS and TAFB forecaster will agree on the shape and size of the “possible” TC development area on the danger chart.**
**TAFB forecaster will make sure that all subsequent text and graphic charts issued by TAFB indicate “possible” TC development****.**

## NHC Tropical Weather Outlook

**NHC Tropical Weather Outlook**
**530 PM EDT (2130 UTC) Sat 07 Sep 2002 **
**A large area of cloudiness and showers**
**extend from the Bahamas northeastward**
**for several hundred miles.  This activity**
**is associated with an upper-level area **
**of low pressure and a surface trough.**
_**There is a potential for tropical or **_
_**subtropical cyclone development**_
_**of this weather system.**_

_**Image courtesy FNMOC**_

_**Classifications 07/1800 UTC**_
**TAFB -  ST=1.5**
**SAB -    TWTC**

**GFS 24 h fcst valid 1200 UTC 08 Sep 2002 **
**MSL and 10m wind**

**GFS 24 h fcst valid 1200 UTC 08 Sep 2002 **
**850 mb wind and relative vorticity**

## Corresponding Danger Graphic

**Corresponding ****Danger Graphic**

_**Result**_
**24 h lead time**

_**1500 UTC 08 Sep**_
**30 kt ST depression**

## Examples of the TAFB Danger Graphic and JTWC Formation Alert.

**Examples of the TAFB Danger Graphic and JTWC Formation Alert.**

**TAFB DG is issued every 6 hours.  While the JTWC FA is issued as needed and updated at least every 24 h.**
**There is coordination between the duty NHC HS, JTWC, and Navy Norfolk when required.**

**JTWC Formation Alert**
**issued 1200 UTC 25 Sep**

**TAFB Danger Graphic issued 0900 UTC 25 Sep**

## Verification of “Possible” TC Forecasts

**2002-2003 forecasts were verified from the TAFB TC Danger Graphic.**
**Events forecasts were verified.**
**The **_**probability of detection**_** (POD), **_**false alarm rate**_** (FAR),  and **_**average lead time**_** were computed.**

## Verification Results of Atlantic Event Forecasts

## Future Changes

**Microwave satellite fixes-2004 season**
**In-house SHIP QC Program**
**Highest wave height during TC event**
**Altimeter data in N-AWIPS**
**Seamless Surface Forecasts Maps coordinated with OPC/HPC/HFO**