The The Hovmöller Report Hovmöller Report as a as a DSS extension in a Weather-DSS extension in a Weather-

Ready Nation™Ready Nation™Robert J. Ricks, Jr.Robert J. Ricks, Jr.

WFO New Orleans/Baton Rouge, LAWFO New Orleans/Baton Rouge, LAWed, August 27, 2014Wed, August 27, 2014

History Lesson…

What is a Hovmoller Diagram?• A way of viewing waves, wave behaviors, density or

concentrations• Also known as a Time-Latitude, Time-Longitude or Time

Section chart• Has been used primarily as a diagnostic tool – but evolving

into a prognostic tool.

“My name is in the [Wikipedia]! I am finally somebody” – Steve Martin “The Jerk”

Applications There are several entities that use Hovmoller Diagrams to show - Tropical Phenomena (NHC) - Madden-Julian Oscillation (CPC) - Rainfall Patterns - Ozone concentrations

Applications

MJO Application

Inspiration/Start-up

• Started in Dodge City, KS in early 1990s based on work by Ed Berry, in collaboration with Jeff Craven.

• Monitoring Wave 3-5 breakdowns which can be impactful for U.S. weather.

• Migrated the technique to WFO LIX 1995 and explored the prognostic aspects of the methodology.

• Used to manually plot and analyze with each 12 hour model run (A labor of love!)

• Started the HAPA Project (Hovmoller Analysis and Prognostic Approach)

Current Approach…• Charts are auto-generated using ESRL

interactive map room graphics (Time Section charts).

• Plotting 500 mb height anomalies over time at a set latitude (20,25,30,35,40) for the entire 360° longitude band (actually 357.5°)

• Resolution: 1 day x 2.5°

http://www.esrl.noaa.gov/psd/map/time_plot/

Black line = target longitude (90W)

Red lines = signals

Orange lines = anchors

So, what are we looking at?• Linear renditions of wave packets moving around the

latitudinal belt. • Cool colors (blues/greens) are negative anomalies or

accumulated angular momentum.• Warm colors (oranges/reds) are positive anomalies.• Ideal signaling is a harmonic rhythm with a nearly

persistent phase speed. (Waves 3-6)• Anchors are persistent standing long wave troughs

(Waves 1-2) • Grid resolution actually serves as a filter for capillary

and highly transient wave lengths.

Prognostic Properties• Once signals and anchors are identified (with

some sense of confidence), they can be extrapolated in time.

• Attempting to find discrete target dates of potential impacts from identifiable signal crossings.

• Not a day-to-day forecast tool. • Most effective for arctic outbreak and density

driven events. • Not as easily effective for severe weather

potential, but some skill can be gained.

Motivation…

1. Try to identify large scale features; downscale to regional and local impacts;

2. Attempt to increase situational awareness for potential weather impacts that may require enhanced services (increased staffing, possible deployments, increased briefing workload, etc.);

3. Bridge the spatial-temporal transition from climate influenced forecasting to weather forecasting;

4. Sanity check for model performance in the long range portion of the forecast process.

5. Science-sharing among peers and researchers.

How is this used for Decision Support Services…• Projecting out 30-60 days. • Focus on large scale, high profile event dates for

NWS offices involved in DSS activities– Festivals– Super Bowls– Air shows– National Conventions– Kentucky Derby– Higher than average confidence weather episodes

• Take the outlook from earliest detection (often 60 days out) up to the 7 day forecast window.

The Hovmoller ReportHovmoller Report• A newsletter to discuss

trends, findings and outlooks.

• Started in 1995, publish about 8-12 editions each cool season.

• Became a Pilot Project extension report for ER-Met activities.

• Multi-scalar (planetary to regional)

Report Contents…• Featured weather story on cover;• Verification of previous outlooks;• Non-met events (volcanic, solar CMEs, sunspots)• Oscillation behaviors (PNA, NAO, AO, MJO);• A brief ENSO status update and some light attribution

to local weather impacts;• Hemispheric wave charts;• Actual Hovmoller diagrams with identifiable signals

and anchors;• Outlook of signal crossings at target locations out next

60 days (with anticipated wx impacts, if possible).

Verification of previous report outlooks

Requested DSS support outlooks from other WFOs

Air Fiesta in Brownsville, TX

Thunder Over Louisville and Kentucky Derby in Louisville, KY

Sample pages…

Sample pages…

Latest hemispheric wave dynamics assessment

Large scale Wave Number behavior

Sample pages…

ENSO state overview

MJO segment

Sample pages…

40N Analysis and Projections with textual details.

Focus was mainly for the Louisville office in this particular report.

Event Climate Data

Sample pages…

30N Analysis and Projections with textual details.

Mardi Gras (Mar 4th)

Jazz and Heritage Festival (2 weeks late April – Early May)

Sample pages…

20N Analysis and Projections with textual details.

Verification and after-thoughts on Air Fiesta event in WFO BRO area that took place Feb 20-23, 2014.

Sample pages…

Oscillation Assessment discussion with interpretation and expected trends

Successes…

• Accurately called for an ice storm in N Louisiana in Feb 1996 with 30 day lead time. – Received SR Service Enhancement Award

• Pretty accurate on last 4 Super Bowl forecasts• Accurately predicted cold and wet Mardi Gras

this year with about a 30 day lead time, despite late season event (Mar 4th).

• Predicted heavy rain event for Gulf States for late March and again in mid-April with a couple week’s head’s up.

Limitations…

• Difficult to account for 3-D energy transfer cross latitude and vertically;

• Non-linear behaviors;• Wave Number transitions;• Visually intensive & labor intensive;• Off-site data source is time delayed about 2-3

days.

Future Developments…

• Attempting to automate the ingest of 500 mb hemispheric data from AWIPS;

• Interactive GUI development to perform analyses and generate signal statistics;– Modeled after “Spectral” Program by Jay Albrecht,

Seattle WA• Increase visibility of Hovmoller ReportHovmoller Report to

possibly include stakeholders;• Tropical Version of technique

Tropical Hovmoller Approach…

• Can do another 30 minutes strictly on this method;

• Viewing U-Winds at 17 levels from 10mb-1000mb;

• Homogenous patterns of easterly and westerly winds in the stratosphere;

• 70 mb is key to the tropical cyclone season• Modulates the season – predictability on pre-

storm development and potential intensity.

Samples… 70 mb Easterly Bulls-eye is where the action is!

89% of all Atlantic Basin systems form within the confines of this feature.

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In closing…• HAPA method has been in practice at WFO LIX for

going on 20 years now. • Hovmoller Report Hovmoller Report has evolved into a DSS

instrument to help bridge the transition from climate realm to weather realm.

• Work continues to implement the approach into routine operations.

• Gaining popularity within WFOs/Centers partaking in DSS activities.

• Promising research on inter- and intra-seasonal tropical cyclogenesis predictions.

Contact Info…

If you wish to be added to the distribution list, please e-mail me.

•E-mail: robert.ricks@noaa.gov•Office phone: (985) 649-0429 ext 4

•Remember, it is called “science-sharing” Comments, feedback, contributions are always encouraged.